3458A - black edition - Page 1
Forum section: electronics / general

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: October 26, 2019, 06:27:47 am
content: Hello folks - the RoHS compliant revised version of the 3458A will be launched soon - 1st of December 2019 - in Germany by Datatec / Meilhaus and authorized KS distributors ... Some of us have already seen the early model or a presentation.Keysight 3458A | 8½-digit digital system - bench multimeter:Back in Black- the legacy model did not meet EU RoHS compliance requirements and was discontinued. Keysight reworked the 3458A fundamentally. In terms of RoHS compliance, Keysight has made a major overhaul of all its printed circuit boards for the 3458A. The revised 3458A is 100% compatible with your existing 3458A.The 3458A Multimeter features an 8½-digit display, an accuracy of 0.0008% for DCV (0.0004% optional), the highest stability of 8ppm per year, combined with very fast measurement speeds with very high absolute accuracy , Therefore, the 3458A is the standard in calibration and calibration laboratories, in production fields and development laboratories around the world.The 3458A is used for high precision DC and AC voltage measurements and DC current measurements. Applications can be found in test rigs for different tasks in meteorological institutes, development laboratories and production, where the high measuring speed is also advantageous.What has been kept unchanged ?Fully compatible: Same form, fit and function. Same specifications as released in 1989. Same programming codes. Same I/O connectivity. Same part number and accessories.What Has Changed?RoHS compliant. New color. New PCB assemblies (DC input board, AC board, A/D board, out-guard controller board, in-guard power supply board, out-guard power supply board). Extended memory (former option 001) is now standard.KS will most likely propel the development of a high end DMM designed from scratch - to be expected in a few years from now.Knowing that KS will focus efforts more on development of new products and the 3458A is more a cash cow - it is right moment to make a wishlist of accessories, software code snippets (Python language), ... that would be welcome with the introduction of the black edition of the 3458A - so that KS can work on that to extend the lifespan of this DMM beast ...What would 3458A adepts like that KS focuses on next coming months ... ?Outdoor carrying case ...Python3 & RPi code snippets ...Improved A9 reference board - 2ppm/YR - lower 1/f noise - lower TC @ lower cost using recent technology...Improved A3 ADC board - new U180 with lower TC - vacuum encapsulation (no leakage)Any other business ... (?)Herzlichen Grüßen/Meilleures salutations/Best regardsScoobyDoo

author: SilverSolder
author_rank: Super Contributor
timestamp: October 26, 2019, 12:34:25 pm
content: "Same specifications as released in 1989."Our ancestors did a good job on this one!

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 26, 2019, 01:04:43 pm
content: And who should do that new 'development from scratch'?These old designers are all gone, so the knowledge about the magic inside the 3458A is also gone.The 34465A/470A is obviously a slight advancement from the 410A/411A only, a lot of copy-and-paste, done by parts of the old development team, which is finally retired.Even this layout redesign has not been done by KS, but an external Engineering bureau, located in EU.I really don't expect any new design any more.Frank

author: iMo
author_rank: Super Contributor
timestamp: October 26, 2019, 01:16:51 pm
content: Quote from: Dr. Frank on October 26, 2019, 01:04:43 pmI wouldn't be so pessimistic. Otherwise they will close the Patent Office soon

author: rastro
author_rank: Frequent Contributor
timestamp: October 26, 2019, 05:08:23 pm
content: It would be nice if sales of the "new" 3458A(BE) would push more of the older 3458A instruments onto the used market.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 26, 2019, 06:10:45 pm
content: There is not that much incentive to change from an old aged 3458 to a new one. There may be a few cases when the choice is repair an old 3458 or buy a new one, that now have a real option to buy a new one.With new fast 7.5 digit meters around the market for the 3458 is now smaller than it was 30 years ago, when it also was the fastest at 7.5 digits. Today the 34470 or DMM7510 may be a good alternative in some cases, when it is more about speed or digital RMS than highest resolution.

author: niner_007
author_rank: Frequent Contributor
timestamp: October 26, 2019, 08:54:45 pm
content: Quote from: Dr. Frank on October 26, 2019, 01:04:43 pmThat’s a myth, and I absolutely do not believe it, if you got the money as a corporation, you’ll get engineering minds to do it from having none or no experience, but it might take a little bit of time, from a year to two years, I have expertise and experience on this topic, you do need experience with hiring, managing and growing people however.With the redesign, I kind of agree, but on different grounds.

author: niner_007
author_rank: Frequent Contributor
timestamp: October 26, 2019, 09:11:26 pm
content: Regarding a new redesign, I would not believe it will be released in a few years, not even close, the new 3458A will be serviced and supported for at least 10 years, as if it were a new product, so maybe 10 years from now we’ll see a new 3458.There are only a few options, 1) they either update and support the 3458A until eventually they don’t, and they get out of the business of making a 8.5 metrology DMM, 2) they make a successor for 3458A that is 8.5 but not metrology grade, kinda like a successor to 34470A, 3) they do a complete redesign and 4) a variant of 1) and 3) where they support the 3458A indefinitely (10-30 years), making incremental updates and localized redesigns over time, making the support scalable.I see 1) or 2) as likely outcomes depending on business outcomes and net profit of Keysight and demand, 3) and 4) are related, and they would be driven by business assertiveness, strategic direction and top down directives.Keep in mind, a complete redesign might very well be a layout and new BOM, but it will never mean not using, previous architecture and designs.I for one hope for 3), and would not look forward to a brand new complete redesign, why? No transparency, no schematics, no component level support and repair and no parts, look at Fluke or look at the 34470, with the 3458A I can buy a new one and used one from ebay, transplant the parts, and go, that is great and unique, that can’t be said of Fluke, or any new test equipment or consumer electronics that comes out and sold today. If all the parts were off the shelf, purchasable from digikey in a quantity of 1, firmware was accessible and transferable, and not locked down and encrypted, that would be a step in the right direction.The 3458A has seen a lot of updates, the digital board is gone and completely different from original, in time they can do the same to the remaining boards, but if they maintain the boards compatibility, that would be killer, no one has done or has that, except the 3458A itself, long term support and component level repair is the dream.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 26, 2019, 10:16:53 pm
content: The problem I see for a 3458 redesign is a rather limited market. There are other meters to offer the low noise / high speed at the 6-7 digit accuracy. So today's market for the 3458 may be well smaller than it was in 1989, when the 3458 was a good option for fast 6 or 7 digit readings.A redesign of the ADC is likely not as easy - not much direct competition to the 3458 (except the new Fulke ones - maybe) and chances are the ADC in the 34470 and similar may not be that suitable to get high linearity. This is more a solution to get the high speed needed for digital AC. Difficulties start with the need to use a JJA to really do a good INL test in the 0.1 ppm range. At his level one may need full boards systems for a test. So design steps slow down quite a bit.Chances are a new design would be quite different today. This could also mean no full software compatibility as there would be different options (e.g. different speeds, different voltage ranges). Still chances are a new design would not be so much better performance , as there are principle limits coming up.I think they did already most of the needed (for ROHs) and easy, small, local improvements. So I don't expect many incremental updates in the near future - maybe a big fix if needed. The black edition is more like the sum of small updates.

author: SilverSolder
author_rank: Super Contributor
timestamp: October 26, 2019, 10:41:30 pm
content: There is significant kudos for Keysight to be selling the leading instrument in its class, creating a halo effect that lifts all of their products.The t&m version of the old Ford motorsport adage,win on Sunday, sell on Monday!

author: iMo
author_rank: Super Contributor
timestamp: October 27, 2019, 07:12:18 am
content: There are two important moments you have mentioned above in your posts - "1989" and "Money".Those great, innovative, highest quality devices (and not only the 3458A) were born thanks the Cold War. The companies like DEC, HP, IBM (and their counterparts in Eastern Block too) and few others milked the Military and Governments in 1950-1989 in an unprecedented way. The military budgets (incl. Space race/exploration) were almost unlimited, hidden, at that time you got money on R&D and the highest-end equipment easily. Those high tech companies were full of money, could afford large R&D teams with most expensive and clever individuals, who worked on designs where $$ played a minor role.After the Cold War finished (1989) most of those companies faced huge challenges. DEC collapsed, HP sold many of its divisions, IBM had restructured as well, many others simply disappeared - as they had to start mess with commercial customers.

author: SilverSolder
author_rank: Super Contributor
timestamp: October 27, 2019, 02:24:07 pm
content: A lot of the high tech developed in the cold war era has now been miniaturized and is "trickling down" to the general population - for example, mobile phones.Test & measurement has moved on too - e.g. the performance of a $20 Aneng 8008 would have been impossible to build in 1989 at anywhere near that price...

author: niner_007
author_rank: Frequent Contributor
timestamp: October 27, 2019, 09:56:05 pm
content: Quote from: ScoobyDoo on October 26, 2019, 06:27:47 amA 2ppm reference for the 3458A is/was already available from Keysight, for a sweet $2000, it can be purchased today, but I believe you’ll have to install yourself and send for calibration. Not available as an option during purchase.What scripts would you specifically want to see? Keysight won’t likely be providing either of one. I’d love to see some C++ scripts targeting Cling (a C++ interpreter), I can use Python, but dislike it, C+/C++ or even C# is my soup :-)Not sure how well this is known, but the 3458A has a built in Basic interpreter, a bunch of scripts that run directly on the 3458A could be useful as well. The interpreter back in the day was probably a killer feature of the 3458A, specially in the 80s when Basic was all the rage.The neat thing about the Pi, is that you can set it up ready to go and just distribute the image (sdcard) or the Pi itself, guaranteed to Plug and Play, and just work.Someone should make a Ubuntu based distro for T&M

author: Henrik_V
author_rank: Regular Contributor
timestamp: October 28, 2019, 11:42:40 am
content: The 3458A is THE standard for a linear ADC.(According to all voltage metrologists I had the chance to talk about that thing)KS invest a lot of work to regain the lost knowledge.The new black edition has the same spec for the ovious reason that a lot of qualified setups will need a one by one replacement, but I wouldn't be suprised if future publications show up some improvements.

author: dr.diesel
author_rank: Super Contributor
timestamp: October 28, 2019, 11:57:04 am
content: Quote from: Kleinstein on October 26, 2019, 10:16:53 pmWhile I agree, I still hope to see a K2002 replacement, the DMM8510. And of-course it had better be LTFLU powered!Though I realize not in the same class as the 3458, but still..

author: iMo
author_rank: Super Contributor
timestamp: October 28, 2019, 12:57:48 pm
content: The big question is how they have replaced those special HP asics, with switches and resistor networks inside. Otherwise the parameters could be better, sure.Also my bet would be they run the old firmware as-is without touching it (ie emulating the old cpu+rams+eeproms+ with a beefy arm).PS: the U180 (38hot.net) among others

author: niner_007
author_rank: Frequent Contributor
timestamp: October 29, 2019, 03:08:50 am
content: if they update the ADC, the 3458A will live forever

author: Kleinstein
author_rank: Super Contributor
timestamp: October 29, 2019, 12:07:33 pm
content: Quote from: niner_007 on October 29, 2019, 03:08:50 amUpdating the ADC can be tricky, even for relatively moderate changes. There may not be an easy replacement for the U180 ASIC, except for a new special chip and resistor array (maybe 2 separate parts). So if U180 is changed - it would be more like a new DMM, no more 3458.

author: iMo
author_rank: Super Contributor
timestamp: October 29, 2019, 12:45:04 pm
content: That would be interesting - I would expect 2 parts solution, as the special Asic would be expensive. Even using two identical parts, but not having them in the same package (do they heat up the U180 inside?) would be worse. On the other hand, the other modern parts around U180 may mitigate the issue somehow, imho.

author: dr.diesel
author_rank: Super Contributor
timestamp: October 29, 2019, 01:03:39 pm
content: Quote from: imo on October 28, 2019, 12:57:48 pmAny reason they simply can't make another run of the original design? Advances in manufacturing might make this affordable over a redesign.

author: iMo
author_rank: Super Contributor
timestamp: October 29, 2019, 01:38:52 pm
content: That is the million dollar questionIt depends on the number of 3458A/BE units KS plans to produce. 10k, 100k, 1mil, 10mil??With 2 "standard modern parts" solution the cost of ie. "U180" could be say $50 in 10k quantities, with a new "old" hybrid chip in that package x0 times more, imho.

author: rastro
author_rank: Frequent Contributor
timestamp: October 29, 2019, 03:21:03 pm
content: There may also be a market for just the ADC PCB as an OEM component for other applications. That would increase the parts volume to mitigate redesign costs.

author: niner_007
author_rank: Frequent Contributor
timestamp: October 30, 2019, 02:00:42 am
content: Quote from: rastro on October 29, 2019, 03:21:03 pmthey should also sell the ADC board standalonethey kind of do, but they assume will be used in 3458As

author: rastro
author_rank: Frequent Contributor
timestamp: October 30, 2019, 12:54:34 pm
content: Quote from: niner_007 on October 30, 2019, 02:00:42 amWho else uses these ADC PCB's in their products?

author: Henrik_V
author_rank: Regular Contributor
timestamp: October 30, 2019, 01:41:54 pm
content: Quote from: Kleinstein on October 29, 2019, 12:07:33 pmThey build a new one to one replacement for the ADC board. All boards can be replaced with new ones AFAIK. There was a live demonstation here at PTB. Old running unit, turn off, replace ADC board with the new one, turn on , recal, DONEI know that there was a time lag due to rebuilding at least one ASIC...To run the ADC board with full spec you need some more stuff... call it a 3458(It's still a big compensation 'computer')

author: iMo
author_rank: Super Contributor
timestamp: October 30, 2019, 01:56:03 pm
content: Quote from: Henrik_V on October 30, 2019, 01:41:54 pmAny shots made at that demonstration?

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: November 03, 2019, 08:44:08 am
content: Quote from: Kleinstein on October 26, 2019, 06:10:45 pmThe 7 1/2 digit DMMs named above have A/D converters derived from older 6 1/2 digit DMMs and we cannot call theseinstruments metrology grade 7 1/2 digit DMMs.e.g. The DMM7510 has a very stable (ovenized) reference, however its linearity is not good enough to call it 7 1/2 digits worthy and units leave factory with sloppy calibration: [+10V/-10V] symmetry is poor and instrument suffers from DC offset once DC inputs shorted. Here the advise is: Try before you buy and compare results with a true 8 1/2 digit DMM.Quote from: niner_007 on October 27, 2019, 09:56:05 pmThe legacy HFL reference board 03458-66529 is still available from Keysight - that is correct.The 2ppm / YR reflects long term drift - these are binned boards - screened over a few months.However semiconductor companies make advances in BZ silicon - Passive component suppliers like VPG, etc. ... make advances in vacuum sealed BMF resistors ... so taking advantage of that knowledge KS could upgrade the 8ppm board 03458-66509 and create a new reference board with better TC and <2ppm long term stability as standard 3458A product at affordable cost. Currently the yield of the 2ppm binning process is not high enough to make it part of the standard product.KS should be agile that it does not loose market share in this metrology arena by believing their 3458A - B.E. is still good enough to beat competition.Quote from: imo on October 30, 2019, 01:56:03 pmSome shots were taken - but attendees were asked not to divulge these pictures as it would alert competition ... and also reveal their identity ...On one of the occasions the unit had still engineering colours - not the final RAL colors that were chosen by marketing.Stay tuned ...Herzliche Grüße/Meilleures salutations/Best regardsScoobyDoo

author: niner_007
author_rank: Frequent Contributor
timestamp: November 03, 2019, 10:32:11 pm
content: Sounds exciting, looking forward to it

author: Zucca
author_rank: Unknown
timestamp: November 15, 2019, 01:42:18 pm
content: Sorry, I posted it in the wrong one:https://www.eevblog.com/forum/testgear/new-keysight-3458a/msg2785490/#msg2785490PS: I am still somehow scared to post here, you guys here have too much brain and experience compared with me....

author: MiDi
author_rank: Frequent Contributor
timestamp: November 15, 2019, 04:05:00 pm
content: Quote from: zucca on November 15, 2019, 01:42:18 pmYou are not alone, I join this club

author: Zucca
author_rank: Unknown
timestamp: November 19, 2019, 12:40:05 pm
content: and the datasheethttps://www.datatec.de/media/pdf/a7/b8/71/Keysight_3458A.pdf

author: guenthert
author_rank: Frequent Contributor
timestamp: November 21, 2019, 04:30:33 am
content: Quote from: Henrik_V on October 28, 2019, 11:42:40 amWell, it's linearity is specified to be better than 0.1ppm. That's also the specification used for Datron 1271/1281 (no longer available) and Fluke's 8508a. Now, I don't mean to belittle the achievement of the HP3458A and it seems that its linearity remains unsurpassed even after 3 decades, but it's not unmatched either (at least as far as specifications go -- individual units might surpass their specifications of course).I further suspect they all share the same specification, not only because of market(ing) demands, but also because it'll be quite difficult to verify better specifications.That all might be idle talk as the Fluke 8508a is considerably more expensive than the 3458a, but with some luck one might fetch a reasonable priced Datron 1271/1281 on Fleebay.

author: niner_007
author_rank: Frequent Contributor
timestamp: November 21, 2019, 05:36:46 am
content: I don’t know about the 8508A, but the new 8588A is $15K, the 3458A with opt 2, extended warranty and calibration with < 0.1ppm uncertainty is $12K, so I wouldn’t call it significantly more expensive, I would even say same ball park.

author: niner_007
author_rank: Frequent Contributor
timestamp: November 21, 2019, 05:42:09 am
content: Quote from: guenthert on November 21, 2019, 04:30:33 amFluke doesn’t give away any linearity figures in any data sheets or specifications, so that claim is inaccurate, AFAIK. Only Fluke reference to linearity figures is in one marketing material, and that has zero technical content, nothing about how it always calculated, what the variation was etc. so little of I can believe personally, as it’s from the marketing department thru and thru, and not the engineering team.

author: e61_phil
author_rank: Frequent Contributor
timestamp: November 21, 2019, 05:51:19 am
content: Fluke specifies transfer and that includes linearity and is the only way you can proper calculate with the linearity.There are JJA linearity measurements with the 3458A and also with the 8508A. So, where is the difference?The 0.1ppm linearity in the marketing section of the 3458A isn't useful as long nobidy defines how you should calculate with that number. Or are you able to show an example calculation?Fluke specifies "linearity" and call it linearity on the calibrators.

author: MiDi
author_rank: Frequent Contributor
timestamp: November 21, 2019, 06:34:46 am
content: Quote from: e61_phil on November 21, 2019, 05:51:19 amIn the spec section there is Transfer Accuracy/Linearity for each voltage range given.Why is that not applicable/not useful for accuracy calculation?

author: e61_phil
author_rank: Frequent Contributor
timestamp: November 21, 2019, 06:49:50 am
content: Quote from: MiDi on November 21, 2019, 06:34:46 amIt is. That is what I'm saying. The transfer spec is the only useful "linearity" spec in the datasheet and that is also given for the Fluke meters.0.1ppm linearity in the head of the datasheet is the same marketing stuff as in the head of component datasheets.

author: eplpwr
author_rank: Regular Contributor
timestamp: November 23, 2019, 11:35:46 am
content: QuoteNope. Got a reply yesterday from Keysight - they will NOT sell me the HFL reference as a spare part. They told me it's "not available", although it's right there in Find-A-Part, with (high) pricing and all ...EDIT: Any suggestions how to get around this "we've got those but wont sell any to you" is most welcome.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 23, 2019, 02:59:15 pm
content: Here are some pictures I took of the new 3458A - Black Edition - at the Munich trade show last week at the Keysight exhibition stand.

author: bsdphk
author_rank: Regular Contributor
timestamp: November 23, 2019, 03:13:40 pm
content: I'm very interested to hear what software version these meters run, if anybody gets a chance to run the "REV?" command I'd be most grateful.

author: dr.diesel
author_rank: Super Contributor
timestamp: November 23, 2019, 03:15:18 pm
content: Quote from: bsdphk on November 23, 2019, 03:13:40 pmThat is a great question!

author: niner_007
author_rank: Frequent Contributor
timestamp: November 23, 2019, 10:04:51 pm
content: Quote from: eplpwr on November 23, 2019, 11:35:46 amDid you call sales over phone? The email guys are always confusing, they told me again and again the ADC board cannot be bought anymore, yet I bought 4 ADC boards brand new, not refurbished, over phone.There might be an exporting clause/restriction too, but they should at least be very clear on that. So in other words, call, with the intent of buying, don’t email.

author: martinr33
author_rank: Frequent Contributor
timestamp: November 24, 2019, 03:38:58 am
content: In the US, I can put the 2ppm reference in the cart and it looks like I can check it out.

author: Zucca
author_rank: Unknown
timestamp: November 27, 2019, 11:57:43 am
content: Quote from: HighVoltage on November 23, 2019, 02:59:15 pmI was there too!!!!

author: IanJ
author_rank: Unknown
timestamp: November 27, 2019, 12:14:36 pm
content: Quote from: zucca on November 27, 2019, 11:57:43 amCouldn't anyone have taken a screwdriver to it when the staff were on their lunch break......😀Ian.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 27, 2019, 04:23:15 pm
content: zucca:We should have arranged a meeting.May be next year.IanJ:I asked to see the inside, they laughed.It even had a padlock, LOL !

author: Dr. Frank
author_rank: Super Contributor
timestamp: December 02, 2019, 10:07:52 am
content: Since yesterday, 1st December, only the Black edition 3458A is offered, worldwide.The old white instrument as well as the EU stock have been removed from all of their websites.Frank

author: iMo
author_rank: Super Contributor
timestamp: December 02, 2019, 11:14:20 am
content: Quote from: IanJ on November 27, 2019, 12:14:36 pmAll we need now is a screwdriver..

author: branadic
author_rank: Super Contributor
timestamp: December 02, 2019, 09:36:59 pm
content: I have seen new A1, A3 and A5 board today. Great work-branadic-

author: niner_007
author_rank: Frequent Contributor
timestamp: December 03, 2019, 03:13:44 am
content: Quote from: imo on December 02, 2019, 11:14:20 amTwo screwdrivers

author: niner_007
author_rank: Frequent Contributor
timestamp: December 03, 2019, 03:14:56 am
content: Quote from: branadic on December 02, 2019, 09:36:59 pmDo tellis it all SMD? did they change the ADC ASIC hybrid? is the PCB multilayer?

author: Andreas
author_rank: Super Contributor
timestamp: December 03, 2019, 05:38:15 am
content: Quote from: branadic on December 02, 2019, 09:36:59 pmphotos pleasewith best regardsAndreas

author: Kjelt
author_rank: Super Contributor
timestamp: December 03, 2019, 08:54:57 am
content: Quote from: Dr. Frank on December 02, 2019, 10:07:52 amThey take that "black friday" thing way to serious at Keysight

author: SilverSolder
author_rank: Super Contributor
timestamp: December 03, 2019, 02:55:49 pm
content: The excitement is building - Who will be first with the scoop?

author: branadic
author_rank: Super Contributor
timestamp: December 03, 2019, 06:08:07 pm
content: Sorry, no pictures that I can post.-branadic-

author: Messtechniker
author_rank: Frequent Contributor
timestamp: December 03, 2019, 06:18:45 pm
content: Meilhaus is advertising this thing as having "improved long term stability".Just wondering how KS did it.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 03, 2019, 07:09:54 pm
content: Improved stability could be from a lower temperature of LTZ1000. The original had a rather high temperature. Such a change may effect the maximum environmental temperature a little. With a few lower power parts (e.g. FPGA, CPU part) the total power consumption could be a little lower and thus less internal heating and warming. On the original board some resistors used for current compensation at the reference are also quite close to the reference and cause heating, where it is not wanted. A new board could have improved on this too.So while the 3458 design was a good and successful there are still a few odd and not so good design decisions. Improvements in the thermal design could be one of the few changes they have to consider. The thermals will change with new and more SMD boards anyway.Other points are hard to change without loosing full compatibility.

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: December 03, 2019, 09:06:56 pm
content: The main reason the 3458As had 15K temperature ratios is because the vast majority of these units were in racks where as many as 5 3458As were mounted on top of each other plus other equipment and the ambient temperatures in these racks very often exceeded 50°C. A lower temperature setting for the LTZ would have resulted in loss of temperature regulation, a big no-no in labs and test facilities. It just wasn't worth the cost and effort to put lower value resistors in units that weren't going into such hot environments. You guys have the option to reduce your LTZ ratios for lower temperatures. The stability specs for the 3458A are quoted for the 15K ratio as it is well known, the LTZ circuit has very low drift with reasonably low TCR components and reducing those TCRs further does not result in significant improvement in drift specs, you have to look elsewhere for that. Selection of the LTZ itself is the only way to get the lowest long term drift rate and that is with a long term burn-in which is 18 months at KS (depending on the target long term drift rate), those are then graded into 8PPM, 4 PPM and 2 PPM/year finished boards, there are no shortcuts.SMD is not the best component to be used in the LTZ circuits, either best metal foil or precision wire wound should be used for top performance and low noise, SMD fits neither of those requirements.

author: Henrik_V
author_rank: Regular Contributor
timestamp: December 03, 2019, 09:29:36 pm
content: My information is that due to reduced power consumption of the new boards (mainly the digital parts I asume) the internal temperature if about 4K lower than in the old units.

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: December 03, 2019, 10:57:55 pm
content: I agree that in theory a 4°C internal drop might help, the point I was making is that the majority of 3458As go into a rather hot rack with multiple instruments generating heat so in that particular case, you cannot drop the 15K ratio resistor to a lower value. Now if the 3458A is sitting by itself with no other heat sources adding to the ambient temperature (say <40°C), plus the 3458A is running slightly cooler due to less self heating, the other circuitry doing the measurements may exhibit a little lower drift and contribute to a slightly better drift component.Any of your 3458As sitting in the open on a table or shelf could possibly show a slightly lower drift overall compared to an earlier 3458A but the ambient temperature is still going to control the overall drift as usual. It has been proven that a fair number of 3458As that have the higher yearly drift specification will in time achieve the same 2 PPM/year drift as the selected models, it just takes longer for the LTZ module to settle in and some never do get that stable. The LM399A can also achieve very low drift rates with time, unfortunately time does not improve noise to any significant degree.

author: jklasdf
author_rank: Regular Contributor
timestamp: December 05, 2019, 05:47:29 pm
content: Just got an email from Keysight about the new 3458A today. It does seem like the main advertised features are just RoHS compliance, the new industrial design, and no *worse* performance than the original. Seems pretty conservative. My guess is they probably would have tried to change as little as possible with the reference and ADC other than for parts obsolescence, even if it could theoretically give better performance.

author: Dr. Frank
author_rank: Super Contributor
timestamp: December 05, 2019, 10:21:30 pm
content: KS needed to keep all versions since 1989 compatible, and especially the specification must not change.I learnt that the reason for that is, that the 3458A is mainly intended for industrial use, i.e. inside manufacturing and testing lines at elevated temperatures, and these production lines are validated / homologized /audited. If you would change the 3458A specification, all these manufacturing lines would have to be re-audited, if an instrument would be replaced.HP did not even improve / adapt the specifications, when several very obvious changes were made in the past, like the much better 40kOhm reference resistor in about 1995.So although the new Black Edition really has many improvements and redesigns, formally / legally it's fully backward compatible.For the very same reason, firmware is unchanged, as well as the interface.On our Metrology Meeting in June, the KS representative already told us, that the DCV noise was halved, and that the DCI ranges are about 10 times more stable, and that the instrument is more stable overall.Maybe the engineering group in charge for this redesign used better shunt resistors, probably similar to the 8085A, from Vishay.Then, all these terminated components, like the EL2008 comparator had to be replaced by other, improved circuits and components. All that cannot be done by simply replacing through hole components by SMD, you have to completely redesign everything.If you think about that further, 8051 and 68000 processors are also obsolete, and a compatible, modern solution had to be chosen.. not difficult to imagine how this was accomplished, and why now the 128kB memory is included.Frank

author: TiN
author_rank: Super Contributor
timestamp: December 05, 2019, 11:16:19 pm
content: Let's make a fundraiser, and buy one forscienceteardown and deep testing.If we get 20-40 really interested people, it's probably could be enough to buy new unit. I'd chip in as well.Then setup Internet to GPIB interface and let everyone online to play with instrument remotelylike I like to do in friends lab.Yes, I know we wouldn't get enough people to spend money just for making $11k teardown.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 05, 2019, 11:53:29 pm
content: Perhaps Keysight would provide a loaner unit for review, if asked nicely?

author: TiN
author_rank: Super Contributor
timestamp: December 06, 2019, 12:36:04 am
content: I did try to ask nicely, but to no avail. Not even "we not interested, thank you for your inquiry". But people did say that "I am not nice" to me before, so ymmv.Also loaners often would mean no teardown, no extended tests (e.g. drift over a year).

author: SilverSolder
author_rank: Super Contributor
timestamp: December 06, 2019, 04:45:45 am
content: Keysight might give Dave first dibs on a review, in recognition of him being behind the collective awesomeness that is the eevblog and its forum.Down the road, something more may be possible. It is is obviously good advertising for Keysight and I doubt their marketing department was born yesterday!

author: MiDi
author_rank: Frequent Contributor
timestamp: December 06, 2019, 08:56:33 am
content: Quote from: TiN on December 05, 2019, 11:16:19 pmInteresting idea.If it was announced that the unit is drawn to one fundraiser, this should get more attention.Before it goes to winner a teardown and 1 year test is done by e.g Dave, TiN.It would be fair, if the chance to win depends on amount of money spent.

author: Kjelt
author_rank: Super Contributor
timestamp: December 06, 2019, 09:32:45 am
content: Quote from: Dr. Frank on December 05, 2019, 10:21:30 pmThanks very informative.What I do not understand is the marketing strategy in this case.They can label it twice and sell at different prices, one as a 3458A with up price for the industrial cases you mentioned, one as 3458B with the improved specifications listed for new customers.Competition is not standing still either, if they now have better specs they should list them to stay in front.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 06, 2019, 12:16:16 pm
content: Quote from: CJay on December 06, 2019, 10:51:16 amA completely new design takes quite some effort and would likely not be fully compatible. At the sub ppm level odd things (e.g. leakage, board DA, acoustic coupling) can become important and it needs a lot of testing to verify the performance. The 30 years of proven use is a big asset for the old 3458.It could still make sense to have a completely new design, especially for the industrial use - a more targeted product (e.g. less priority on the AC part) could be a lot cheaper to produce and lower power. A new design would likely be more like the DMM7510 with a separate slow and fast ADC. This simplifies things a lot. Despite the effort the 3458 ADC in the fast mode is still no match for modern SAR chips. A multi-slope ADC for only the slower part (e.g. 1 ms and longer integration) is easier, but would still need some experience and knowledge beyond the text books. However a design with 2 ADCs would not be fully compatible anymore: it can be better in many aspects but could be slightly lower specs in the intermediate range. The ADC in Keysights 34410, 34470 and similar is quite different from the 3458: good and maybe even better at higher speed, but limited (still sufficient for there use) linearity.P.S.The original 3458 ADC kind of relies on high performance JFET switching and thus the special ASIC. It still possible to produce such a thing, but it still is expensive and there may not be much improvement from the last 30 years. A different design could use cheaper MOS switches possibly even of the shelf parts.

author: bsdphk
author_rank: Regular Contributor
timestamp: December 06, 2019, 01:49:58 pm
content: Most likely not. HP's "silicon on saphire" process was quite special.

author: MiDi
author_rank: Frequent Contributor
timestamp: December 11, 2019, 11:29:07 am
content: For those who did not follow the other Thread (of the many that are there):Keysight gave some details

author: syau
author_rank: Frequent Contributor
timestamp: December 11, 2019, 11:29:49 pm
content: Looking forward for Daniel to send an unit to TiN

author: notfaded1
author_rank: Frequent Contributor
timestamp: December 12, 2019, 04:52:08 am
content: Idk about it not having to be somewhat redesigned... Some things just aren't practical anymore... If it is someone is going to be able to beat it I bet... and sooner than later. I'm sure fluke is working on it. So much can be done with new generation ASICs and combined with general purpose processors the stuff that can be done in software alone is amazing. It's what's made all the new Cisco network switches able to do software defined networking. This year the big news was 400G Ethernet for God's sake. I work with custom ASIC hardware engineers every day and the technology is so far beyond 5 years ago it's incredible. I have a hard time believing time can just keep standing still...Bill

author: TiN
author_rank: Super Contributor
timestamp: December 12, 2019, 05:45:40 am
content: notfaded1While ASIC advancement for digital stuff is indeed progress with light speeds, that does not apply to analog domain. And no matter of digital power, math or smart logic, none of that can help much to make better analog performance front-end/ADC device, when you already pushing the limits at ambient temperatures. Digital algorithms are as good, as your input data is. If you feed garbage at the input, you only get nice looking garbage at the output. Even new Fluke meters with fancy touchscreens and pretty UI still will have tough time matching even 3458A original design from 1989. Call me a fanboi, but I'm not going to replace my old 3458A's any time soon. It's hard to imagine, but digital ASICs are VERY different to high-performance analog ASICs which often need special materials/processes and manufactured by 180 nm or larger nodes. This tech is on the opposite very difficult and expensive spectrum of the chip design, compared to fast and dense digital stuff.Another limiter factor is voltage reference. No matter old meter, or new one, they already are reaching limits of what noise/long-term stability can be achieved using very best reference money can buy, such as LTZ1000A. And even that needed special selection and aging, before device can be put into each specific DMM.Adding fancy Ethernet, high power hungry TFT with touchscreen and cloud-data uploading and blockchain to the meter like 3458A isn't very important for people who spend $11k+ on this instrument. Many applications and customers might still use 3458A as very fast and accurate DMM in automated test jigs. For all they care, there could be no front panel version and it would still sell just fine.Only wish I would improve on 3458A probably would be better ohm functionality and electrically-switched front/rear input, so it could be used as direct comparator in metrology labs. But it's not big deal, one can always use external scanner and 5720A calibrator for advanced needs.

author: FrankBuss
author_rank: Unknown
timestamp: December 12, 2019, 06:05:24 am
content: Quote from: niner_007 on October 27, 2019, 09:56:05 pmThere is already a project for the Raspberry Pi for many instruments:https://www.eevblog.com/forum/metrology/raspberry-pi23-logging-platform-for-voltnuts/It has some Python examples, for the 3458A as well, see here:https://github.com/PlesaEEVBlog/RPi_LogNut/tree/master/pythonI used this with my Fluke 8842A and worked nicely. But meanwhile I'm using Debian Linux on my main desktop system for daily work, and managed to install the GPIB driver on it with the help of the installation scripts on the voltnuts repository. Now I can just run the Python scripts from my desktop, which is even easier than the additional step to the Raspberry Pi.Example how I recently used it, with an updated version of my voltage logging script, and then using Google Sheet to create a diagram of the recorded values:https://www.eevblog.com/forum/dodgy-technology/9900-mah-18650-accus/msg2725094/#msg2725094

author: Kleinstein
author_rank: Super Contributor
timestamp: December 12, 2019, 10:56:33 am
content: There are a few points that could be improve at the 3458. The relatively easy part would be changes in the digital part, like adding standard SCPI support (if not already done) and a few more statistics features.Another point would be reducing the power needed, so the meter can run cooler - this alone could improve some leakage specs.It could be in deed very difficult to beat the 3458 as a direct 100% compatible replacement, because of the rather special ADC that is accurate and fast in one unit. A more modern design would likely go for 2 separate ADCs: one for the slow modes (e.g. 1 ms and up) and one (e.g. good SAR chip) for the fast modes. The fast part is relatively easy as modern chips already beat the 3458 ADC at the higher speeds. Not needing the high speed modes can help to get better low speed performance.With modern CMOS switches one may not even need such a special analog ASIC with JFET switches to build a good ADC. It could still help to get a custom CMOS switch chip - but this is no real magic and nothing that special. One may even get away with of the shelf chips. Much of the custom chips are more like custom resistor arrays of very good quality. The reference part is still relatively easy - the LTZ1000 reference is still available and the A9 board (ref) can still be the old design.However a completely new design from scratch would not be 100% compatible. So even if better there would still be demand for a direct replacement. However even if inferior in some aspects a good one could cover much of the market, especially those who only something like a fast 7 digit DMM. Chances are the 3458 is not as linear anymore when using 1 PLC or faster.

author: notfaded1
author_rank: Frequent Contributor
timestamp: December 12, 2019, 11:38:43 am
content: I get that no matter what you do you can't change physics... but let's use my field as an example. Many times we thought we had reached the limits of Moore's law. Time and time again we've destroyed the limits shrank and improved on processor speed at closer to room temperatures. Perfect example are the materials... many scientists thought we had reached the limits of silicon... well IBM strained the silicon and put other materials next to it and low and behold our architectures are now orders of magnitude smaller and faster and work without super cooling. Just look at the how the transistor has changed. We no longer have 2D silicon it's now 3D. My point is... Everytime scientists said it can't be done... we did it with new novel technology. I work with many RF engineers and what they're done with radios today is just short of amazing. Our Holy Grail right now being sought is quantum encryption. Unbreakable encryption where any observer can be detected. I will say this the RF engineers I know do stuff today that's black magic to me. Sometimes they do seem like a dying breed but there are new RF engineers coming out of college. The older generation is always saying the younger engineers are missing something and low and behold they come up with something that changes the entire game. Just like you were saying... Analog ASICs... for all we know analog devices could have a new product in development we don't know about. I wouldn't ever count out the engineers I see as interns today.Bill

author: Dr. Frank
author_rank: Super Contributor
timestamp: December 12, 2019, 12:21:35 pm
content: I'm justabout all of your speculations, w/o any substantial background.Please take for granted, at least from what the KS sales man has told us @ Metrology Meeting, that the black 3458A has been redesigned by an external engineering group in Germany, and that many parameters have been improved. I already mentioned 1/2 DCV noise, and that's simply because now, 30 years later, much better and less noisy transistors are available, but that's not the only reason.branadic has already seen the interior of the new 3458A, so you may guess where and why.Henrik_V obviously also has seen the black 3458A live at the PTB , when they demonstrated the swapping of A/D boards. Guess why @ PTB.. probably they were also involved in theimprovementof the A/D converter, where else should that happen, alternatively in Loveland facility only. Here again, you may guess that of today, better OpAmps, better PCB material and more knowledge about layout techniques are available, than 30 years ago.Frank

author: notfaded1
author_rank: Frequent Contributor
timestamp: December 12, 2019, 01:23:41 pm
content: That'll be great then Doc... if you need a new A/D board for your 3458 you can still buy a black edition one and put it in your old 3458. Sounds like a win for existing labs to meIt also means many of us probably won't be getting one anytime soon.Bill

author: SilverSolder
author_rank: Super Contributor
timestamp: December 12, 2019, 03:00:15 pm
content: Quote from: notfaded1 on December 12, 2019, 01:23:41 pmThe good news is that we are very close (if not there already) with viable hobby level A/D designs that can approach 8.5 digits (see other threads in this forum).It seems to me that kind of project is the next step up from building your own LTZ1000 etc. reference... and could be very entertaining to try to achieve!

author: FrankBuss
author_rank: Unknown
timestamp: December 12, 2019, 07:17:38 pm
content: Quote from: SilverSolder on December 12, 2019, 03:00:15 pmI don't think this will be possible anytime soon. It is a big step from a voltage reference to a fully working DMM, especially with this accuracy.But maybe something less accurate, like the Fluke 8842A, would be possible to build yourself. I couldn't find a circuit diagram for the 3458A, but there is one for the 8842A. Someone would just need to replace the obsolete parts with modern parts, then reverse-engineer the ADC algorithm, and then it might be possible to build it cheaper with a modern microcontroller.

author: SilverSolder
author_rank: Super Contributor
timestamp: December 12, 2019, 07:33:29 pm
content: ^Of course a hobby level effort is never going to be an industrial DMM like Keysight's flagship, but people on this forum have achieved spectacular results within the limitations that you only have DC volts and one range. These efforts will only get better in future, it seems to me.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 12, 2019, 08:18:10 pm
content: Quote from: FrankBuss on December 12, 2019, 07:17:38 pmThe Fluke 8842A with it's recirculating reminder ADC is a pretty odd starting point to build a DIY high resolution ADC. I would consider this more like variant of a pipelined successive approximation ADC. The adjustment alone is a nightmare.The more classical multi-slope ADC (e.g. like the 3458, 3456 or Keithley 2000) is a much more promising starting point. Unless one needs the high speed of the 3458 there is no need to use a run-up so fast. Less frequent switching reduces demand on the switches so that normal CMOS can get you quite far. The real difficulty is very good linearity - this starts with the problem that verification of linearity better than 0.1 ppm pretty much needs a JJA. At this level it is also not just the circuit diagram - a not so good layout can also ruin things. Not all the higher order effects that contribute to INL at the 0.1 ppm level may be known. So a new board for the ADC can be a big deal.

author: bsdphk
author_rank: Regular Contributor
timestamp: December 13, 2019, 08:27:25 am
content: "Unless one needs the high speed of the 3458 there is no need to use a run-up so fast."That may be true at the margins, but it is certainly not true in general.Fast-ish conversion is important for accuracy, as it keeps a lot of time-variant effects at bay.Note though, that even the original HP3458 hardware could have run faster, but the speed was reduced to hit the sweet spot between different noise-sources. (It's all in the original HPJ article, if you read carefully.)

author: TiN
author_rank: Super Contributor
timestamp: January 10, 2020, 04:02:34 am
content: Some interesting box showed up today with Keysight Technologies label on it. Wonder what that could be...Ah, right....

author: e61_phil
author_rank: Frequent Contributor
timestamp: January 10, 2020, 04:24:48 am
content: Quote from: TiN on January 10, 2020, 04:02:34 amThat's easy. It's a power supply

author: Zucca
author_rank: Unknown
timestamp: January 10, 2020, 08:20:35 am
content: Quote from: TiN on January 10, 2020, 04:02:34 amit's the num 5, I bet the other four n 1-2-3-4 are on the other side of the room.

author: iMo
author_rank: Super Contributor
timestamp: January 10, 2020, 08:22:31 am
content: But we need pcb shots instead

author: HighVoltage
author_rank: Super Contributor
timestamp: January 10, 2020, 09:37:07 am
content: Why is it that I am not surprised that TiN is the first one with a black edition?Wow!Yes, now inside pictures please!

author: chuckb
author_rank: Frequent Contributor
timestamp: January 10, 2020, 03:30:08 pm
content: You will of course have noticed that the "3458A Multimeter Assembly Level Repair Manual" on the Keysight Website was updated for the Black edition. No update of the the schematics yet.https://www.keysight.com/main/techSupport.jspx?nid=-31940.1242732&pid=2905513&cc=US&lc=eng&pageMode=PLIncluded are some low resolution Pix of the PCB! Looks like DIPs replaced with SMD. Parts are in the same place.A1 DC Input has new input relays, one Hermetic resistor in the current measurement section (no change), a rectangular black module near the voltage ref connector.A9 LTZ1000 Voltage Ref looks the same.A3 ADC finally has an updated, small, logic controller. Can't tell about U180, it's still under the shield.Part Number for new A1 03458-66511Part Number for new A3, 03458-66523Part Number for new A9, 03458-66559 (normal, 03458-80009 (opt 2)There are no photos for the new PCB in the replacement parts area yet.

author: notfaded1
author_rank: Frequent Contributor
timestamp: January 10, 2020, 07:28:48 pm
content: That's pretty awesome TiN the Darth Vader 3458 and you got one already! What's the device sitting on top of it called that seems to match it perfectly in color and looks like it's monitoring V and A from multiple inputs? It looks like you've already hooked a ton of stuff up to it already as well! Hopefully you can tell us soon everything different about it and it's brothers? Those shield boxes you have over the inputs or outputs on some boxes looks interesting too.Bill

author: MiDi
author_rank: Frequent Contributor
timestamp: January 10, 2020, 08:12:27 pm
content: Number 5 is alive!And it has a printed version of the HP Journal on topWho would put an inventory sticker on something borrowed?

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 10, 2020, 09:34:11 pm
content: Nice, and congratulations! Please do a Tear-Down and a characterization, please.The black 3458A and the 5720A seem to agree within 0.01ppm.. even nicer.Now please check DCV impedance, bias, noise, INL of DAC. If you can, noise spikes from the multiplexer, in comparison to the old instruments.Check stability of DCI in terms of T.C. and time and consistency against 5720A artifact calibration.FW should be 8 or 9, as it didn't change. U180 also did not change.From pictures of the Repair Manual, take notice, that all the logic and the 68000 is included inside one gate array, apart from SRAM and Flash firmware.On the A/D board, logic and µP obviously also was crunched into another GA.. how many layers does this PCB have, in comparison?Btw.: An original paper version of hpj 4/1989 is still down in my basement lab... together with the complete original manualsFrank

author: iMo
author_rank: Super Contributor
timestamp: January 10, 2020, 10:03:26 pm
content: U180 in plastic flatpack?

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 10, 2020, 10:28:17 pm
content: Quote from: imo on January 10, 2020, 10:03:26 pm

author: iMo
author_rank: Super Contributor
timestamp: January 10, 2020, 10:34:23 pm
content: Or is it covered by the shield (5) there in the picture?

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 10, 2020, 10:54:43 pm
content: Quote from: imo on January 10, 2020, 10:34:23 pmYou've got it!

author: Macbeth
author_rank: Super Contributor
timestamp: January 10, 2020, 11:21:26 pm
content: OMG, the absolute madlad has only gone and done it! Looking forward to the calibration checks vs Fluke 5720A and the ultimate teardown

author: TiN
author_rank: Super Contributor
timestamp: January 10, 2020, 11:39:35 pm
content: QuoteAnything below 0.2ppm is just nonsense, unless we are pouring helium.I've tricked output for a pretty photo.Actual deviation between 5720A and 3458ABE from Day 0 is -1.2 ppm, which is not bad too.I've calibrated primary 5720-5725 in August using 792X LTZ1000A FX reference, which was in turn calibrated to NIST PJVS 10V system at ITRI CMS NML.My resistance capability is better, since I handcarried my SL935, calibrated to PTB QHR chip / National MINTL standards at ITRI CMS NML same time August as well.3458ABE shows -0.19 ppm error on 10 kOhm resistance range vs 5720A as result, even with <24 hour warmupMy SR104 is at different friendly lab location, and I am not shipping it back until it's warm and nice outside to avoid any chance of stress. Don't want to loose it's <0.1 ppm/year capability.QuoteBorrowed original HPJ issue from a friend of mine too, for pretty selfie.I'm getting also some more 8.5-digit reinforcements from FedEx next week, and my lab will back to 8x8 DMMs again

author: bsdphk
author_rank: Regular Contributor
timestamp: January 12, 2020, 12:40:18 pm
content: Hi TiN,What does REV? report for the black edition ?Does the XYZZY command still work ?

author: notfaded1
author_rank: Frequent Contributor
timestamp: January 13, 2020, 04:37:44 pm
content: Personally I think that SL935 is the neatest thing! I watched the video when you were rebuilding the oven for it and reversing the schematic with the trimmed resistors. Really impressive as long as it's running it doesn't need a bunch of math to compute the TC curve like the SR104 basically because it maintains it's temp in search of the zero slope. 8x8 DMM's o.O! I can only imagine what you have planned for the ABE! We can live vicariously through you TiN.https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1989-04.pdfBill

author: Wolfgang
author_rank: Super Contributor
timestamp: January 17, 2020, 04:55:32 pm
content: Quote from: SilverSolder on October 26, 2019, 12:34:25 pmUnfortunately, yes. I think they changed the bare minimum to get it thru the ROHS procedure.All the unpracticalities are still there:- Spooky and fading VFD- No USB or LAN connectivity, only GPIB (in 2020!!)- Antique operationThey are sending me marketing emails every week, but I think buying a well-hung one running for 10 years will have less drift than a new one.In the meantime I try to survive with my 34470A, and most of the time it works very well (used for thermal drift measurements).

author: SilverSolder
author_rank: Super Contributor
timestamp: January 17, 2020, 11:26:15 pm
content: Quote from: Wolfgang on January 17, 2020, 04:55:32 pmIt is a little sad that "our" generation can't seem to move the state of the art forward in a meaningful way. The same malaise as aerospace and other industries seem to suffer from.

author: Wolfgang
author_rank: Super Contributor
timestamp: January 18, 2020, 12:45:09 am
content: I would not be so pessemistic. You can still buy a Fluke or a Transmillle (both for some extra money), but they are up-to-date and should work fine.HP is just trying to get away with a minimum investment, I am convinced they could do better if they really want.

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: January 20, 2020, 08:00:14 pm
content: Hello - there is an article in EDN about the 3458A B.E. :https://www.eetimes.com/metrology-grade-dmm-gets-a-new-colors-is-that-really-news/?utm_source=newsletter&utm_campaign=ad&utm_medium=EDNTestMeasure-20200120#Herzliche Grüße/Meilleures salutations/Best regardsScoobyDoo

author: SilverSolder
author_rank: Super Contributor
timestamp: January 20, 2020, 10:56:18 pm
content: Quote from: ScoobyDoo on January 20, 2020, 08:00:14 pmI guess the only way for Keysight to introduce an advancement would be to introduce a whole new meter, that people could slowly "switch to" in their own sweet time.

author: Wolfgang
author_rank: Super Contributor
timestamp: January 21, 2020, 12:55:08 pm
content: Quote from: ScoobyDoo on January 20, 2020, 08:00:14 pmI think Keysights conclusion that they could not change anything because the users would never want that is pure marketing bullshit and an excuse for no improvements.Of course they could:- officially sell a 2ppm version (and ask a good price for it)- make a 2020-style LCD like on the 34470A- incorporate USB and LAN interfaces- modernize SCPIit would still be possible to incorporate a "vintage mode" to fully emulate the old instrument so existing users have a drop-in replacement.I agree that black paint and ROHS PCBs are a lot easier to make. Marketing does the rest if real innovation (once a HP motto) is absent.

author: exe
author_rank: Unknown
timestamp: January 21, 2020, 03:48:16 pm
content: As far as I understand, we don't know yet what was done and how much effort was put into it. Although, yeah, seems weird nowifilan in default configuration. Can it be added as an option by replacing a communication card?I don't think "current generation" cannot do it. To me it seems a matter of demand. I won't be surprised if most sales are in gov/mil areas.

author: LazyJack
author_rank: Frequent Contributor
timestamp: January 22, 2020, 10:24:44 am
content: I'M pretty sure they did the market research and concluded that none of these would sell as many additional units, that would warrant the development cost. I'm also sure they did the math and figured that making the black edition will recover the costs.This is such a niche product, that I don't think anyone outside the metrology industry would have any idea on what new features are needed or economical to implement.

author: Henrik_V
author_rank: Regular Contributor
timestamp: January 22, 2020, 12:44:52 pm
content: Be shure KS asked around in the metrology community about new features for a future 3458B version.However, as already noted: this community is conservative ( add very,more or most) ...(VFD is known to work for 20+ years ... how about OLED? , as long as I can get spare parts: no problem*)On my list: better sync between instruments .. (RefClock IN/out, have 2+ ADC boards in 'perfect' sync) , ethernet*) I like my V543 Nixi DMM I'm able to read without glasses, even in 20 years

author: Wolfgang
author_rank: Super Contributor
timestamp: January 22, 2020, 03:26:16 pm
content: Not sure everything was done so well-planned and deliberately.Probably more like this:1) Sales: Shit. We cannot sell our 3458A anymore to Europe because of this bloody ROHS stuff.2) Management to engineers: Whats the cheapest way to get around that ?3) Engineers to management: We can leave all circuits as they are, but we need to make new PCBs and buy lead-free components4) Management: OK, do that. And paint it black so it at least looks different and new.5) Engineers: done.6) Management to Marketing: Make a campaign about the "new" 3458A and explain why "no change" is a lot better than improved specs, a better user interface or long missing interfaces7) Markting: Groovy ! Almost no investment, no improvement, still looking as new. Lets write a few journal articles that make us look smart.

author: dr.diesel
author_rank: Super Contributor
timestamp: January 22, 2020, 03:50:39 pm
content: As funny as that is, and probably more correct than we'd like to admit, there is also don't fix what ain't broke!If the limited customer base is happy, then just do what needs to be done and move on.Though I'd really like to have seen ethernet added.

author: e61_phil
author_rank: Frequent Contributor
timestamp: January 22, 2020, 04:36:43 pm
content: I fully agree with Wolfgang, but I don't think the 3458A has a only a small group of customers. Most of the electronic design labs I know have, at least access to, a 3458A. Most of them aren't chasing the last ppm of absolute voltages. They use it to verify drift of circuits or measure extreme values, which are difficult with other meters.In the time I worked in the university, we had one (new and then uncalibrated) which was used to verify all the 6.5 digit meters. I ask Agilent that time, what they think how often a calibration of the 3458A is needed for that job and the answer was: Never

author: TiN
author_rank: Super Contributor
timestamp: January 23, 2020, 12:55:56 am
content: QuoteQuote from: 3458A BlackQuoteQuote from: 3458A Black

author: niner_007
author_rank: Frequent Contributor
timestamp: January 23, 2020, 07:45:19 am
content: those are small changes, improving the current and AC ranges on the other hand would be a better investment, who cares GPIB or not, disable the VFD display and just fully control it over GPIB

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 23, 2020, 08:07:28 am
content: The best engineering in the world took place from the 60s to the 80s, no one has the ***** to redesign the hardware of software of the 3458A . Even a organisation the size of Boeing can't design a new plane and get rid of the 737 frame jeez

author: bsdphk
author_rank: Regular Contributor
timestamp: January 23, 2020, 08:51:47 am
content: Thanks!This confirms that they have not touched the software.To me that makes a lot of sense, in terms of getting to a point where they can sell new meters.Updating the outboard side would be a major undertaking on its own, involving a fair bit of software archaeology, but it is not impossible.Commercially it would be stupid to have that delay the RoHS hardware roll-out.However, I think they will have to deal with it eventually, and therefore I would not be surprised if we see a 'B' upgrade, which only changes the outboard card.Looking at it, I think you could fit both a USB and Ethernet connector in the GPIB cutout on the backside, thus making the A->B upgrade available to all ages of meters.(And if they havn't found anybody to do it yet, my company does stuff like that for money :-)

author: SilverSolder
author_rank: Super Contributor
timestamp: January 23, 2020, 01:19:08 pm
content: Quote from: MasterTech on January 23, 2020, 08:07:28 amI think there is a lot of truth to that."Boldness has genius, power, and magic in it." -- GoetheHow many modern committee driven cross functional teams achieve boldness, genius, power, and magic? We lost the plot somewhere along the line.

author: e61_phil
author_rank: Frequent Contributor
timestamp: January 23, 2020, 01:36:16 pm
content: I absolutely don't agree. Your very focussed on that very old DMM. There isn't much room for improvements. The reference one would use today (30 years later) would still be the same. The linearity is also good enough for the needs one would have. It would be very hard to be a factor of two better than the old instrument and it doesn't make much sense to put a lot of effort in something for such a little improvement.Airplanes are a complete different story. I fully understand to not change more than absolutely needed, to avoid the huge pain with compliance and so on.There are many enigneering fields which still improve rapidly. Also in the region of measurement technology. RF stuff for example. Or bigger instruments like mass spectrometers and so on.

author: Wolfgang
author_rank: Super Contributor
timestamp: January 23, 2020, 01:52:43 pm
content: I think the 3458A improvement potentials are obvious:- 4ppm / 2ppm option (for a hefty price, probably). They could be painted in gold instead of black- modern GUI LCD (like the competitors, Fluke and Transmille)- USB/LANIMHO they will move their ass only when challenged by a competitor with a product doing better for a lot less money.Not for all, but for a lot of applications, the 34470A is a viable alternative even today.In the meantime its like mainframe computers; they slowly die out, but you can still make a lot of profit from people than cannot leave the platform.

author: iMo
author_rank: Super Contributor
timestamp: January 23, 2020, 03:28:08 pm
content: The next step is to go cryogenic - to keep the entire stuff at around -273K. Something like a single chip meter with all the dividers and shunts put into a small Dewar bottle. While kept cold the noise and TC drift and aging will be almost zero. The entire meter of 34401A box size. It will come in a few (10-20) years, I bet.

author: SilverSolder
author_rank: Super Contributor
timestamp: January 23, 2020, 03:33:58 pm
content: Quote from: e61_phil on January 23, 2020, 01:36:16 pmI would challenge that notion. - How about a DMM with a built-in Josephson junction reference, for example. The work would be to miniaturize it and make it viable. That's what our ancestors would have done - you know, the guys that went to the moon, the ones that designed the airframes we still use - if they had our technology. We are completely effete in comparison.

author: iMo
author_rank: Super Contributor
timestamp: January 23, 2020, 04:12:30 pm
content: Quote from: imo on January 23, 2020, 03:28:08 pmOk, the mankind gets lazy, no willingness to spend XX% of their GDP for the space or arms race..Thus I should have been more conservative - "It will come till end of this century, I bet"..

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 23, 2020, 04:13:01 pm
content: Quote from: e61_phil on January 23, 2020, 01:36:16 pmI'm not referring to improvements, but to unique feats and leaps forward that won't be repeated again by comparison. Tektronix developed a 250ps pulse generator and a 1GHz analog scope in the 60s, the fastest highest flying plane was developed in the 60s (SR-71, *everything* is unique about this plane), the first high-bypass turbofan engine (same concept as still used today) was developed in the 60s, men were flying out there in the 60s, I could go on an on... You can put all the ethernets and USB ports on a 3458, or increase a spec analyzer from 3GHz to 30GHz but these are not feats at all.

author: Wolfgang
author_rank: Super Contributor
timestamp: January 23, 2020, 04:24:42 pm
content: Disagree. Not all is lost.If you look at an 110GHz Keysight UXR scope or on a R&S FSWP phase noise analyzer, we *can* make landmark innovations if we want (and the marketing people let us).The problem seems to be the bureaucracy around the inventors - they slow down everything and kill everything that does not stink like fast money.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 23, 2020, 04:45:22 pm
content: A problem with those high end DMMs is that there is a rather limited market. For most cases one does not need a super low noise meter as the voltage source one is looking at will have much higher noise. One usually only sees the combined noise of the source and meter. So it is only with those very low noise source, that may be used in metrology that one really gets a real advantage from a very low noise meter.The 3458 also has one big asset - it's reputation and history. So the minimal changes are understandable.Because many of the old meters still get maintenance and repairs, it does help if the boards are interchangeable - this also limits possible changes.It seems that they did not change the ground referenced software (at least not much). This is at least the easier part.Updates to the software an GND references part would be a area that looks possibly, as it does not need slow and expensive new testing of the analog part. I can understand that the priority is to meet RoHS so one is sure one has the hardware, before one invests in SW updates or extra features.

author: niner_007
author_rank: Frequent Contributor
timestamp: January 23, 2020, 07:46:57 pm
content: with Helium coming in thru the multimeter? that wouldn’t be feasible size wise, if anything, I want the DMMs to be smaller, not larger, and not very wise system engineering; there’s also the other components, like resistors, capacitors, and ultimately the PCB itself, the reference is just a small parton the other hand, you could have the reference external as an option, in the same way some instruments can use a more stable external clock

author: ramon
author_rank: Regular Contributor
timestamp: January 24, 2020, 07:59:36 am
content: Quote from: Wolfgang on January 22, 2020, 03:26:16 pmManagement: Is there anything that needs to be improved or fixed?Engineers: Yes, there is a problem with a custom asic in one board that makes the device drift out of specs, it has happened even on new units. The customer either needs to pay us a few thousands (if not covered by warranty) or then they need to sell the unit on the second hand market. This makes the second hand market full of faulty units that don't meet spec that cannot be recovered into service again without '$,$$$ help' from us.Management: Ok ... Understood. Just make the ROHS change, nothing else. And be sure that this custom asic works in the same way for this new version.Quote from: Wolfgang on January 22, 2020, 03:26:16 pm

author: niner_007
author_rank: Frequent Contributor
timestamp: January 27, 2020, 08:24:43 am
content: The 30 years of compatibility is a strengths though, no matter what the underlying reasons for the smaller or larger update might have been on the Keysight part, we should be grateful for it, even if it was fueled by reduced investments and cost cuts. For the ASIC, unless you have at large failure data, it's a moot point, for all we know the 8588A has similar failure pointsWe might never know, we don't have access to the data, and likely the Fluke DMM will be obsoleted 10 years from nowTouchscreen, LAN, WiFi, USB, you name it, can absolutely be done, and for little effort on the Keysight side, but why, such UX improvements would be pretty useless, that's not how (and if, it should not) these multi-meters are used. Keithley did the touch screen treatment in DMM7510, and even has some pretty advanced triggering and state machine construction directly in the multimeter, but as long as you have to do something more elaborate, it all gets to down to scripting or remote control, and it all falls down. Never mind the insane number of bugs causing all sort of crashes still lurking around in the DMM7510. You hit one of these crashes, you say goodbye to your memory buffers.Unless it's analog improvements, you too should not be interested in itAnd if improvements are made, I very much would prefer them to be iterative and maintain compatibility, that's a hell of a feature to have for over 30 years, the only other system with such compatibility might be Windowslol

author: bsdphk
author_rank: Regular Contributor
timestamp: January 27, 2020, 08:44:38 am
content: "Touchscreen, LAN, WiFi, USB, you name it, can absolutely be done, and for little effort on the Keysight side"I will dispute the "for little effort" part of that claim.As much as we drool over the gorgeous hardware in the 3458A, more than half the magic is in the software.While there are things you can do to improve that firmware, adding "Touchscreen, LAN, WiFi, USB" with "little effort" is not one of them.Just moving the firmware to a CPU which does not execute mc68000 instructions would be a major undertaking, due to the way command-dispatch is implemented.Ensuring that the new firmware measures *exactly* the same way as the current firmware would take a lot of effort over a couple of years.Of course one could design a UX unit with a touch-screen, which pretends to be the existing screen & keyboard electrically, but it would be intolerably slow.Likewise, one could stick a small embedded computer on the GPIB to offer USB/LAN/WIFI interfaces, but that would increase the command latency.I'm pretty sure that if you poll the people who pay list-price for new 3458A's, they will either tell you that they press a few buttons to do ACAL and to select what to measure and have nothing hooked up to GPIB, or they have something hooked up to GPIB which they *really* do not want to have to change in any way, because it is part of the certification of their manufacturing line.In other words: Yes, everybody would absolutely expect better UX and interfaces on a new design, but to the paying 3458A customers adding that would be a good reason to look for a different solution instead.

author: SilverSolder
author_rank: Super Contributor
timestamp: January 27, 2020, 01:18:11 pm
content: Quote from: bsdphk on January 27, 2020, 08:44:38 amThis is why it might make more sense to develop an entirely new DMM with few backward compatibility concerns as an upgrade path, while leaving the 3458A as it is.

author: Andreas
author_rank: Super Contributor
timestamp: January 27, 2020, 08:46:02 pm
content: Quote from: bsdphk on January 27, 2020, 08:44:38 amHow do you keep your Fluke 732 (specced 0.18V/m max field strength) away from such a EMI-Source?No real volt nut wants avoidable RF near his measurements.With best regardsAndreas

author: rodpp
author_rank: Frequent Contributor
timestamp: February 20, 2020, 03:02:13 am
content: Quote from: TiN on January 10, 2020, 04:02:34 amHi @TiN, could you already share some data about the black 3458A, better yet, compared with the old 3458a model?Thanks!

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: February 20, 2020, 05:32:36 am
content: Guys this is from the horse's mouth (Keysight), the specifications of the 'black' 3458A is the same as the beige 3458A, yes there were changes made. It seems that the folks over in the EU was making a real stink over the 3458A having a handle on it so they declared that it did not meet the exemption requirements as it had previously even with the handle being on there all along. The main reason for putting a bunch of SMT in it was because some of the old leaded components were becoming difficult to obtain as was the MC68000 CPU system chips, so where necessary they had to substitute where possible for components except where it was prudent to stick with leaded components. The software was a real challenge to keep it backwards compatible with the original system, it basically emulates the MC68000 in software. The LTZ sub assembly was left alone as it was a proven design. They did nothing to disturb the original design, it works just like always.While there were some small difference such as a little decrease in system power for instance, they said the specifications will remain the same, if they were to change them then the unit would be called the 3458B.I agree with Dr. Frank, the speculation was nothing more than that.

author: rodpp
author_rank: Frequent Contributor
timestamp: February 20, 2020, 05:49:48 am
content: Yes, I believe that changes were minimal.But nothing better than data to show that the performance remains the same.

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 20, 2020, 07:25:20 am
content: Quote from: Edwin G. Pettis on February 20, 2020, 05:32:36 amSorry Mr. Pettis,the rumors you have replicated here, do not match the truth. At our Metrology Meeting in Stuttgart last year, we have received reliable details from KS, and that the redesign has been done here. So there's no speculation from my side, either.The 3458A was redesigned, because many components were really obsolete, like the infamous ELANTEC comparators, and many others.It's obvious, that the engineers then chose up-to-date RoHS compliant SMD components, wherever possible and useful. That has nothing to do with the EU, FLUKE has done the same on their DMMs also.There were several improved parameters, although this is not reflected in the specification, due to compliance requirements.The 68000 processor is definitely NOT emulated in software, and the firmware is not changed at all.Please remember, that there exist cores from several FPGA suppliers and projects for 68000, 8051, so it's quite straightforward to merge most of the logic of the controller and the A/D board into single ICs.Frank

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: February 20, 2020, 05:02:53 pm
content: Quote from: Dr. Frank on February 20, 2020, 07:25:20 amHmmm, seems like a tempest in a teapot, Dr. Frank. Actually, everything I read from Mr. Pettis, above, seems to have a basis in everything you say, too!. Not sure why there is the beginning vehement statement from you about unsubstantiated rumors? Could not the opinions of a Keysight engineer in the US, for example, differ from one in Germany? Lets not go to personal attacks.

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 21, 2020, 12:38:02 am
content: Quote from: RandallMcRee on February 20, 2020, 05:02:53 pmDefinitely not.I just don't like to be cited as to spread speculations.I either publish my personal opinions or observations I've made, or I publish facts-If you or others read carefully, both cases can be distinguished easily.Frank

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: February 21, 2020, 04:51:39 am
content: Well Frankie, take a pill, calm down and let the adults speak, according to Keysight USA, you know the home office, the 3458A has been and always will be 100% designed, developed, and the redesign was 100% done in the the USA. The main manufacturing facilities are in Malaysia with a special facility on occasion in Singapore, they will also manufacture the 3458A wholly in the USA if the customer requires it (such as the military). While thee are R&D facilities in Belgium and Ireland, there are 5 facilities in the US in including one here in Colorado where I reside. Outside of the R&D facilities, the other Keysight facilities in Europe only deal with local issues in applications and software, no design work.They said the redesign of the 3458A was completely done here in the USA as was any other changes, the firmware is 100% compatible with previous units.As part of the agreement when Keysight was split off from Agilent, Keysight agreed to change the color of all of their instruments to this black (marketing picked it) you are seeing, all of the newer designs are already in black and most of the legacy instruments have been changed over, the 3458A being one of the last ones to change.....that is all the color change is, nothing more.Perhaps there was a misunderstanding in Stuttgart but this is what the home office is saying and I have no reason to believe what they are saying is false. You are welcome to call Keysight here yourself.

author: MiDi
author_rank: Frequent Contributor
timestamp: February 21, 2020, 05:17:48 am
content: Independent from Stuttgart meeting I got the information, that at least A3 board was developed in Germany.Maybe @Henrik_V wants to contribute.

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 21, 2020, 07:35:58 am
content: Quote from: Edwin G. Pettis on February 21, 2020, 04:51:39 amHello Edwin,that history of hp and agilent and Keysight, I know all that, also that the 3458A was initially designed and tested in Loveland, before 1989.The 344xxA DMM platform was the last redesign project by several engineers of the old staff from that era, but obviously they all are gone, or being retired.These instruments are all hp-white, so what's that fuss over the black color?Sorry, there is absolutely no misunderstanding (and no speculation), all the new boards have been redesigned outside the KS organisation, by an Engineering agency, located here in Germany.I don't have to call Keysight, because this information came first-hand from Keysight Germany.Frank

author: Zucca
author_rank: Unknown
timestamp: February 21, 2020, 08:17:15 am
content: Like in aviation: If only we could see what's inside the black box...

author: branadic
author_rank: Super Contributor
timestamp: February 21, 2020, 08:40:11 am
content: I've visited the german company that redesigned the A3 board myself last year and saw some different design stages of the A3 board as well as all the parts they needed to build it, including multiple U180 and entire 3458A in the different design stages, even one that was just painted black to match the new "design", the lab, some test environments and the like.It's no disgrace to except that Keysight needed help from outside their country to get that challenge on 3458A done. But if it is easier for you to live with, believe whatever you want to believe.-branadic-

author: Wolfgang
author_rank: Super Contributor
timestamp: February 21, 2020, 09:34:55 am
content: ... whoever made this remarkable achievement to put a 30 year old 68000 processor into an FPGA and integrate some glue logic,still nothing to be very proud of. I think that at least a USB interface plus a reasonable display could have been integrated as well,with no effect on backward compatibility. The major innovation here is black paint.

author: Zucca
author_rank: Unknown
timestamp: February 21, 2020, 11:22:01 am
content: Quote from: Wolfgang on February 21, 2020, 09:34:55 amKS did not want innovation in this project.KS had two pure main marketing (not innovation) goals in this project:- RoHS- absolutely backwards compatible to the white 3458AThey not even change the name for a reason. It isnota 3458B.It this way KS can continue to sell this first place golden standard DMM to everybody again as before, no requalification needed.Best bang for the bucks, well done KS!

author: notfaded1
author_rank: Frequent Contributor
timestamp: February 21, 2020, 11:35:07 am
content: I'm just glad I finally got one and I don't even care that it's white!!! I see no reason to argue too much about US vs German engineering. Most companies spread engineering out across all their offices these days. With teleworking we have engineers in multiple states and multiple countries all working on the same piece of a project often. I'd be willing to bet that was case here as well. We aren't limited to doing one project in one place anymore.Bill

author: iMo
author_rank: Super Contributor
timestamp: February 21, 2020, 01:32:46 pm
content: The origin of the re-engineering effort depends on the effort's result, afaik from my previous work with large multinational corporations:Success - HQFailure - Engineering Company off-shore

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: February 21, 2020, 06:10:45 pm
content: In the long run it really doesn't matter where what was done or by whom, only that the 3458A is still the same machine to the user, it is identical henceforth there was no model change, it is still the reliable 3458A.There is really no need to get irate about the details.To some degree, yes they could have added more bells and whistles but it is apparent that the customer base is not interested and adding those bells and whistles would contribute to more EMI inside the unit and also require re-certification and I don't think that was a viable option.

author: ramon
author_rank: Regular Contributor
timestamp: February 22, 2020, 06:26:59 am
content: ... yet nobody has shown any proof ... I am with rodpp!

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: February 22, 2020, 08:24:21 am
content: Gentlemen - as long as my direct Keysight info is correct - Keysight Böblingen (Germany) commissioned the facelift of the A3 (ADC) board of the 3458A to a small engineering bureau near Munich in collaboration with PTB - PTB assisted with the verification (testing) of the INL of the A/D converter board.The early 3458 B.E. units had a dark blue-ish colour as one of the engineers repainted the panels in some sort of local garage (paintshop) and some photos - shot during a PTB meeting - were spread "by accident".As we had seen those PTB pictures and discussed it among engineers and Metrology Voltnuts we asked Keysight (USA & Germany) to send a knowledgeable speaker to divulge more info of the 3458A B.E. during first Metrology seminar - organised late May in 2019 (https://www.eevblog.com/forum/metrology/volt-nut-meeting-2019-in-stuttgartgermany/). This year the event is planned in beginning of June (info: BRANADIC - Dr. Frank - ... ) and again we invited knowledgeable speakers (from that german engineering bureau and Keysight Germany) to unveil more details of this remarkable project on next event early June 2020. I would say mark your diaries and be there ... - the organization is in hands of Hahn & Schickard (info: BRANADIC) and resides on and near the campus of the University of Stuttgart - a very nice place for Voltnuts to visit ...Our major concern:We have observed that many spare boards (A3 ADC, A9 03458-66529 2ppm ... ) have been withdrawn from public sale - and new 4ppm and 8ppm VREF A9 boards were introduced at much lower cost than before - I strongly "guess" (not info from controlled source) Keysight is encountering a yield problem as we observed prices of the new A3 board sky rocketing before boards were withdrawn - I hope this is only temporarily until they control better the yield of the boards in the factory in Penang - Malaysia. A lot of the success of the old 3458A was contributed by the fact that the unit could be repaired endlessly - and I hope that Keysight continues to follow that former strategy in making available all spare parts for the 3458A owners community as they did in the past.Herzlichen Grüßen/Meilleures salutations/Best regardsScoobyDoo

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: February 24, 2020, 05:27:09 pm
content: well, with all your concerns, all is not lost. just trade it in for a 20% discount.-scnr, that gave me a good chuckle!(approximate) translation: "trade-in youroldprecision multimeter for a new fluke reference multimeter 8588A or 8558A and save up to 20%!"

author: Wolfgang
author_rank: Super Contributor
timestamp: February 24, 2020, 05:36:53 pm
content: Yeah, why not ? Slightly better specs, modern LCD, USB/LAN interfaces, and a 3458 compatibility mode.Fluke has also been selling reference multimeters or decades. How much would this one cost ? (3/4ppm version).

author: TiN
author_rank: Super Contributor
timestamp: March 01, 2020, 05:17:58 pm
content: Just a status update about 3458A Black review progress. I have collected lots of data and had nice photoshoot, and currently busy checking data and doing additional tests on my own 3458A's and other meters used in comparison. Black meter is back at Keysight now, and I plan to release review this month, including nice juicy thread in EEVBlog Metrology.Overall I'm happy with Keysight teamwork on this, very pleasant experience indeed. Not every day you get to try out brand new instrument, so some credits go to EEVBlog voltnut community too.Want to make it nice and comprehensive with Python test apps used in performance verification, good plots to show highlights. All that takes time to do right. I have my primary 10V and 10 kOhm standards out for traceable calibration at the moment to confirm absolute accuracy data I've collected.If you want to have short summary : everything you know about original 3458A is also valid for new one. It works like 3458, feels like 3458, so it is same 3458A. That applies to performance as well. Unit I had in test was STD production instrument, manufactured in December 2019. Noise, tempco and other secondary performance results show that it is average 3458A, inside of the Keysight specifications. This particular unit is not a replacement to golden special 3458A's that some of us have, we might want to wait for 9.5-digit DMM for that.

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 01, 2020, 05:58:25 pm
content: Quote from: TiN on March 01, 2020, 05:17:58 pmFor 9 1/2 digits, you need a less noisy LTZ1000 / LTFLU / zener replacement.Frank

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 01, 2020, 07:09:30 pm
content: Quote from: Dr. Frank on March 01, 2020, 05:58:25 pmThis is what amazes me... with all our new technology we still can't seem to build a better mousetrap. We can build quantum computers but still can't seem to build a better zener?B

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 01, 2020, 08:06:15 pm
content: Quote from: notfaded1 on March 01, 2020, 07:09:30 pmNope. The zener diode will ALWAYS be that noisy.You need a replacement for that technology, i.e. a voltage reference which is NOT based on the zener effect.Frank

author: Kleinstein
author_rank: Super Contributor
timestamp: March 01, 2020, 09:14:48 pm
content: The LTZ1000 zener is not perfect in a sense that it can not be made better. It may be one of the best zeners currently available, but chances are it can be done better: some of the Chinese DW232 seem to be lower noise, the unheated TC is not that low as with the LTFLU and some of the bare die pictures show luminescence (thus likely some surface contribution and not a perfect buried zener). Chances are the noise of the LTFLU may be a little lower. If really needed one could use multiple reference together. For a real reference meter a combination of something like 2 or 3 reference would be a good idea anyway to get at least a cross check.Anyway, except for metrology, there is a very limited need for such a very high resolution / low noise. There is limited need for a noise level much lower than the DUT.The 3458 is not that special for it's reference or noise. The really special point is the linearity, and there are not that many meters that only come close. Noise wise the 34470 is not that different, but the linearity is a different class.

author: niner_007
author_rank: Frequent Contributor
timestamp: March 01, 2020, 11:06:53 pm
content: Quote from: Wolfgang on February 24, 2020, 05:36:53 pmBecause you'd be losing at least some $5000? Look at the ad, it has the new 3458A in there as well not just some 30 year old random unit.

author: Henrik_V
author_rank: Regular Contributor
timestamp: March 02, 2020, 08:30:12 pm
content: Quote from: notfaded1 on March 01, 2020, 07:09:30 pmWait.. there are some better units... involves liquid He, a HF source ..drawback: it's no zener anymore.. and you have your perfect 10V (or n times xV) in a cold bottle .. and you need to get it out to the heat .. and you don't want eddy currents in the bottle circulating forever.. and ... and ..

author: Wolfgang
author_rank: Super Contributor
timestamp: March 02, 2020, 08:45:59 pm
content: What you could think of is *parallelizing* references for low noise. 10 chips ca. 1/3rd of the noise.

author: MiDi
author_rank: Frequent Contributor
timestamp: March 03, 2020, 06:10:47 am
content: Quote from: Henrik_V on March 02, 2020, 08:30:12 pmMeh, ancient technology back from the 80s everywhere...Essentially no improvements since more than 30 years...Not even miniaturisation and better energy efficiency...Still waiting for the cheap pocket quantum standards...

author: Wolfgang
author_rank: Super Contributor
timestamp: March 03, 2020, 10:40:41 am
content: Spooky green VFDs and GPIB rulez !! Retro black is the new smart. The fanboys objected any change.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 03, 2020, 12:50:42 pm
content: Quote from: Wolfgang on March 03, 2020, 10:40:41 amIt is OK to keep the old meter the same, for all the reasons that people have given (compatibility with existing setups, certifications, etc. etc.).What we need is a NEW meter, one that adds another order of magnitude of performance!

author: Wolfgang
author_rank: Super Contributor
timestamp: March 03, 2020, 03:05:21 pm
content: IMHO, no one insisted on VFD and GPIB only. They insisted on upward compatibility, which is fully OK.The rest is marketing blabla and the intention to get away from the ROHS issue with the minimum investment possible.

author: bsdphk
author_rank: Regular Contributor
timestamp: March 03, 2020, 09:57:56 pm
content: "IMHO, no one insisted on VFD and GPIB only."You could change the VFD to any other display technology you want, glyph for glyph. The display has its own controller so that would not require any software changes, but doing so would not sell a single extra meter.Changing what is displayed would require a significant investment in software modifications, and would probably not sell more than ten or twenty extra meters for them.Changing the external interfaces to the outboard processor, would require a major investment in software, it is not "just" in any sense of that word, and it would probably not seel more than an extra ten or twenty meters either.If Keysight wanted to do any of those things, the only sensible way to go about it is to get the RoHS meter out there to keep the revenue stream going, and then introduce a B model later, which has the same in-guard boards, but a different out-guard controller, frontpanel and backpanel.Depending on the production and long term experience with the RoHS in-guard boards, and in particular actual customer feedback, (as opposed to various volt-nuts without purchasing budgets in some quaint but not revenue generating forum), they might also update the specifications at that time.I do not expect that to happen.(But again: If Keysight needs somebody with the necessary code-archaeology skills, I'm available :-)

author: Wolfgang
author_rank: Super Contributor
timestamp: March 03, 2020, 10:50:25 pm
content: See it as you like,there is no excuse for boutique vintage parts like VFDs and antique interfaces in 2020 except short-sighted profit maximisation.Of course they can do better than that, after 30 years !!I think a company being lucky enough to have a succesful product in the market for 30 years needs not to be pitied if a major redesign is due. The ROI period of the 3458A is very long over, so come on, start moving.

author: MadTux
author_rank: Frequent Contributor
timestamp: March 03, 2020, 11:15:54 pm
content: Wonder how many of those LCD DMMs end up smashed during shipping/rough handling/accident with soldering iron etc. in the next 20 years.Graphical LCD also needs fancy display controller, usually with integrated flash memory. As soon as the flash cells leak out, you have an expensive brick, if the firmware is nowhere available.I don't need any graphical interface on any DMM/SMU (can be done remotely, if needed), simple LED display (like in HP3456A) is enough (alphanumerical such in Keithley 236/237/238 is especially nice). Robust, lasts forever and can bereplaced easily.VFD is nice when new, dimming at old age sucks however. Also fails more often than LED, is more fragile and usually needs difficult to get parts for high voltage drive signals.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 03, 2020, 11:37:26 pm
content: Quote from: Wolfgang on March 03, 2020, 10:50:25 pmSometimes, simple is better. GPIB can still do things that more modern interfaces can't. For example, trigger multiple instruments at exactly the same time? ... the most important feature is probably being able to play well with other instruments that all have GPIB...

author: Wolfgang
author_rank: Super Contributor
timestamp: March 04, 2020, 01:12:37 am
content: GPIB still has a few merits, but is simply dying out in the new instrument generation.I think the reason why some people are willing to accept all the retro user interfaces and missing functionality is that they dont work with this as a lab instrument, but as an automated test tool in production or QA. Nobody will ever look at the output of the meter, and nobody will press any keys, all runs under remote control.I need something like this in lab work changing every day, and therefore I want a compatible look and feel as my other meters (e.g., 34470A) and Keysight benchtop instruments.A smart solution would be a PXI-based box for the remote control people and something really up to date for the lab guys.

author: CalMachine
author_rank: Frequent Contributor
timestamp: March 04, 2020, 04:25:45 am
content: Quote from: Wolfgang on March 04, 2020, 01:12:37 amI think you are way off base and as someone who used 3458a in a metrology lab for years, I would vomit if they released PXI version. In my experience, PXI bus is nothing but a hassle.I, for one, am glad they kept the VFD and GPIB interface. Replacement parts are relatively cheap and readily available. I don't foresee your wanted LCD display lasting 30+ years as the original 3458a hardware has... and when that display goes out? Better get ready to fork over $$$$$.

author: bsdphk
author_rank: Regular Contributor
timestamp: March 04, 2020, 06:03:47 am
content: "I think the reason why some people are willing to accept all the retro user interfaces and missing functionality is that they dont work with this as a lab instrument, but as an automated test tool in production or QA."And you know what ?Those "some people" make up 99% of the HP3458A sales.

author: Wolfgang
author_rank: Super Contributor
timestamp: March 04, 2020, 08:47:50 am
content: Quote from: CalMachine on March 04, 2020, 04:25:45 amI dont think VFDs have such a good reputation for longevity or reliability. Also on the 34401A the display has been a comon weak spot.VFDs are boutique parts even today. Readiliy available in 20 years to come to repair todays 3458As ? Rather not.

author: Wolfgang
author_rank: Super Contributor
timestamp: March 04, 2020, 08:49:29 am
content: Quote from: bsdphk on March 04, 2020, 06:03:47 amAs the comments in this forum show, your 99% are probably an exaggeration. My guess is 60 to 70%.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 04, 2020, 12:24:09 pm
content: Quote from: Wolfgang on March 04, 2020, 08:47:50 amVFDs can be reliable, if done right. I have a couple of 1970s era HP 59304A GPIB displays that use some type of gas discharge technology. When I got them, they showed every sign of having been run constantly on for 30 or 40 years... but simply cleaning the film of dust from the inside of the transparent red front panel filter/lens made the displays as bright as new. Nothing needed fixing... just cleaning! Even the three bulb indicators still worked...

author: TiN
author_rank: Super Contributor
timestamp: March 05, 2020, 01:27:53 am
content: I rather prefer 3458A's easy interface and front controls, which are very quick and easy to use after you program hotkeys to typical operations, than modern flashy LCDs which are mostly horrible for view angles, have menus upon menus inside the menus and require grunty processors, switching power supplies and other drawbacks in instrument. Sure, LCD is great to have for general every day bench, or on the scope, but forcalibration/automated systemDMMs it is not functional importance.And "modern look" or "antique controls" or "vintage feel" or "smooth multi-zone touchscreen" are not very relevant when you paying $11k+ for a professionaltoolfor a job to do.

author: oPossum
author_rank: Super Contributor
timestamp: March 05, 2020, 01:54:14 am
content: Quote from: SilverSolder on March 04, 2020, 12:24:09 pmProbably a Panaplex display. Similar technology to Nixie tubes but has a cathode for each segment rather than a cathode for an entire digit.

author: TheSteve
author_rank: Unknown
timestamp: March 19, 2020, 05:25:50 pm
content: While we wait for high res pics we can at least see the new A3 in low-res courtesy of Keysight.

author: syau
author_rank: Frequent Contributor
timestamp: March 20, 2020, 12:36:56 am
content: Quote from: TheSteve on March 19, 2020, 05:25:50 pmU180 still thereFPGA and associated 5V interface chips similar to those newer A3 board and the 8051 became SMD.

author: MadTux
author_rank: Frequent Contributor
timestamp: March 20, 2020, 01:27:09 am
content: Quote from: Wolfgang on March 02, 2020, 08:45:59 pmWhy isn't this done on chip/die level already?Like doing the LTZ1000 reference circuit like 16 times on a small ovenized chip assembly to get 4x lower noise than normal LTZ1000.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 20, 2020, 08:42:48 am
content: On chip level a larger area device can be used instead of multiple parallel one. AFAIK the LTFU already has 2 zener structures in parallel.For the LTZ1000 more current for the reference also gives more heat and this requires a higher temperature or more power to the heater and possibly a different case design. In principle the LTZ1000 reference could run with a slightly higher current for lower noise - but with possible downside of more drift.For a DMM 2 parallel references have an additional potential benefit over just noise reduction: 2 reference allow some basic consistency check to detect excessive drift of one reference. So it adds to the reliability.Because the new boards are meant as a direct 1:1 replacement, a additional 2nd ref. board would be difficult to implement. The space and power would not be so bad, but it would also need some signal routing and different firmware. So this would be more like a point to the wish-list for a possible future new design.

author: iMo
author_rank: Super Contributor
timestamp: March 20, 2020, 10:06:47 am
content: Quote from: MadTux on March 20, 2020, 01:27:09 amI think the yield (the number of "good" chips/dies you get off a silicon wafer) with voltage references is low.Therefore putting 16 references into a single chip (a single monolithic silicon die) would be risky and the yield would be much lower.The good option would be a "hybrid chip device" or "multichip module" - ie. 16x LTZ1000 individually preselected dies put on a ceramic carrier, with some supporting stuff (thin/thick film technology), put into a larger hermetic metallic package.

author: Henrik_V
author_rank: Regular Contributor
timestamp: March 20, 2020, 03:04:07 pm
content: Put 20 on the die, and offer a 4/8/16 version .. laser laser

author: Macbeth
author_rank: Super Contributor
timestamp: March 21, 2020, 08:38:25 pm
content: Quote from: syau on March 20, 2020, 12:36:56 amIs U180 still in production? I figured they had a finite supply of old stock but with a new board and meter are Keysight actually still getting them manufactured in that old school package?

author: niner_007
author_rank: Frequent Contributor
timestamp: March 22, 2020, 03:00:32 am
content: Quote from: Macbeth on March 21, 2020, 08:38:25 pmOf course it is in production, how could they still manufacture new meters or sell the bare boards, if they didn’t

author: MadTux
author_rank: Frequent Contributor
timestamp: March 22, 2020, 12:09:26 pm
content: Quote from: niner_007 on March 22, 2020, 03:00:32 amNew old stock, ie they made a big load of U180 dies during production run and stashed them somewhere?Now they only need to package those. Once they run out of U180 dies, no more new 3458A?

author: Kleinstein
author_rank: Super Contributor
timestamp: March 22, 2020, 12:29:05 pm
content: The U180 hybrid chip is a main part of the ADC. Redesigning this would be quite some effort with expensive testing. So it is absolutely no surprise to still find it. With the relatively large chips inside, the old THT case may also be a good choice for a hermetic case.I don't know if they still have a current production or just sufficient NOS, either finished or just bare dies. The quantities are still small, so if won't be production every week anyway, more like every few years a new batch.Just for the mounting holes and cable lengths they can't make the boards much smaller - so th new board picture is not such a large surprise. Staying rather close to the old version is natural even of the new chips are smaller.

author: notfaded1
author_rank: Frequent Contributor
timestamp: March 22, 2020, 09:19:06 pm
content: I don't see any reason why you wouldn't keep producing them... if it's not broke... don't fix it.

author: e61_phil
author_rank: Frequent Contributor
timestamp: March 23, 2020, 09:04:04 am
content: Quote from: notfaded1 on March 22, 2020, 09:19:06 pmBut it is...The ADC drift problem seems to be a problem over many years now.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 23, 2020, 09:47:02 am
content: For the drift problem it is not so clear if this is really solved. It is also a relatively expensive part to produce.So there are some arguments to avoid the U180 chip in a new design, but for the 3458 it is the essentially part for the ADC.So no surprise to still see the old style U180 - it would not be a 3458 anymore without it.

author: voltampere
author_rank: Regular Contributor
timestamp: March 23, 2020, 05:43:21 pm
content: Not really hires....But a bit clearer,regardsJoerg

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 23, 2020, 08:03:07 pm
content: Many Thanks,There's the Wekomm logo in the right bottom corner, a small non occupied 'test structure' beneath, probably a hex inverter 7404, 5 inverters in parallel, driving something, maybe a 'pigtail' optoisolator (U10).No 8051 µP, instead that ALTERA CPLD, probably 5M1270Z, everything else as described.Let's search, which fast comparator they've used..Frank

author: iMo
author_rank: Super Contributor
timestamp: March 23, 2020, 09:03:47 pm
content: TL3016?

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2020, 09:18:18 pm
content: Enough evidence that wekomm made this board, nice, thanksUnpopulated Broadcom / Avago HFBR-1521Z and related logic gate for external clock.-branadic-

author: Kleinstein
author_rank: Super Contributor
timestamp: March 23, 2020, 09:20:03 pm
content: The comparators looks like TL3016 with additional clamping on the input, so they don't need a +-18 V supply. It is readable for U181.This looks like a sensible choice.The part around U181 still looks as odd as the original: Buffer the signal with an LM358 to send it to a super fast comparator to drive a resistor of some 600 K.This part of the circuit never made sense to me and chances are the comparator is disabled most of the time, except during some self tests.

author: TiN
author_rank: Super Contributor
timestamp: March 23, 2020, 11:18:28 pm
content: Dr. Frank8051 uC is little TQFP chipie with a label. So everything is there

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: March 24, 2020, 01:08:06 am
content: Where is the integrator cap? that part of the layout looks changed as well.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 24, 2020, 11:39:26 am
content: The integration cap is C119, right at the bottom of the board.There are some changes to the placement, but not really much. The general layout is similar.There are also some changes to the circuit and values: e.g. 2 diodes each at the slope amplifier, larger resistors and thus a smaller capacitor at the output of the LT1001 in the integrator.No longer the large decoupling caps (C120,C121) at the integrator (at least not on the top side - there could be an tantalum cap on the bottom, but I doubt it).

author: Echo88
author_rank: Frequent Contributor
timestamp: March 24, 2020, 11:54:42 am
content: Is it correct that theyve never corrected the U180-microcrack-issue?

author: iMo
author_rank: Super Contributor
timestamp: March 25, 2020, 12:01:02 pm
content: Posters close to we-komm there in DE may ask them on U180 details..

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 25, 2020, 12:59:20 pm
content: The statement from Wekomm was (I think I already posted it here), that U180 is still in actual production by KS and has seen several revisions over the years.

author: voltampere
author_rank: Regular Contributor
timestamp: March 29, 2020, 04:13:52 pm
content: Does that mean i should expect a rather "fresh" version on my new A3?How shall i interpret the printing on the sticker?1NC1-0017903-4/03My very uneducated guess here would be -> April 2004!Now i am scratching my head....RegardsJoerg

author: martinr33
author_rank: Frequent Contributor
timestamp: March 29, 2020, 05:08:29 pm
content: Handling marks and handwritten magic marker numbers would seem to support the idea of an older date code. However, poking through some pictures and boards, I don't see a consistent numbering scheme for U180 that would lead to a firm conclusion.What I do see is a consistent pattern of hand-written "magic marker" numbers. That pattern goes back a long way, and I wonder if it isn't some part of a pre-screening process for the packaged chips.Also, the scratch on the chip suggests a fair amount of manual handling.I did find this piece of trivia:http://www.icproto.com/ab-profile.htmlThis looks like the company that used to package the ASIC that HP was using, until they replaced the ASIC with the daughterboard. The ASIC appears with brands Promex and Orbit, both brands associated with Quik Pak. Maybe the original vendor (Fujitsu) dropped support for the part, or the package, or both.

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 29, 2020, 05:12:53 pm
content: Would have been fortunate that you first had a look on xdevs site, there are several different pictures of different A3 vintage, to afterwards make an educated guess.So let me google it your you.. Obviously, U180 rarely has a unique D.C., neither that the format is standardized.As your A3 board is assembled in 2019, that 903 seems to be the D.C.4/03 is probably never used as a date format on semiconductors.

author: syau
author_rank: Frequent Contributor
timestamp: March 30, 2020, 12:13:17 am
content: Photo for some recently acquired board in March 2019

author: chuckb
author_rank: Frequent Contributor
timestamp: March 30, 2020, 01:16:48 am
content: Some defective U180 chips from bbs.38hot

author: syau
author_rank: Frequent Contributor
timestamp: March 30, 2020, 06:12:24 am
content: Quote from: syau on March 30, 2020, 12:13:17 amThis board was a "Test Fresh Board" with Compl Date 21 Dec 2018.The marking on the U180 is 1NC1-0017 730-1/17 (Hand written 49) on another "test Fresh Board" with Compl Date 11 Jan 2019

author: iMo
author_rank: Super Contributor
timestamp: March 30, 2020, 10:59:30 am
content: My guess would be the 0017 or 0108 is the production date (17w 2000, 8w 2001), the string like 1NC1, 1SJ8 is the revision code, and the 3digits number there is the Serial number (like 014, 812, 040..) within the batch (like they cook 1000 hybrids in a batch).

author: voltampere
author_rank: Regular Contributor
timestamp: March 31, 2020, 08:50:44 pm
content: Wow....Lots of guesses.Let me sum up:a) my ( seemingly ) stupid guess -> april 2003 ( could be march 2004 as well...)b) academic backed guess of "Dottore" Frank -> march 2019c) imo's guess -> week 17 of 2000Personally i would like Frank's guess the most, because it would mean that my chip is rather fresh.Anybody who knows about the scheme for the marking?Best regardsJoerg

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 31, 2020, 11:38:21 pm
content: Quote from: voltampere on March 31, 2020, 08:50:44 pmHi JörgAkademisch basiert? So ein Quatsch. Ich habe vielleicht ein bisschen mehr Erfahrung mit Date Code Formaten, auf Grund meines Jobs.Das hier ist eine einfache Mustererkennung.. wenn überhaupt mal ein Anzeichen eines Date Code zu erahnen ist, in all den Beispielen, dann stimmt dieses dreistellige oder vierstellige Fragment immer ungefähr mit den Date Codes der anderen Bauteile auf der Leiterplatte überein, und diese ganzen anderen Ziffernfolgen eben nicht, wie zB 0017, das kommt doch schon seit 20 Jahren auf dem IC vor.Dieses ewige Spekulatius hier ohne jegliche Logik, oder irgendeine Begründung warum das so sein sollte, nur ins Blaue rein, was den Leuten so gerade einfällt, das geht mir echt auf den Nerv, sorry.Wäre toll, wenn das MM doch noch stattfinden würde, dann könnte man die authentischen Leute dazu befragen.Frank

author: martinr33
author_rank: Frequent Contributor
timestamp: April 01, 2020, 03:17:20 am
content: The real test will come when you check the drift on the part.Some of these are pretty much zero drift, but some are not. The part looks pretty much the same as it has been for decades, and it still goes through the magic marker process. The board says, "Made in Malaysia", so it is going to use the same production parts as the previous version.I'd tag the whole board at somewhere in September 2019 (week 42).Now - what did they do to replace that Elantec super high speed comparator? Looks like they might have used this part TL3016 - except it took 3 parts to replace one Elantec 3016. The TI is faster, but has higher offset currents.Hmph - the TI part is 5V only, so it needs regulators, which is what the other parts look like. I still wonder if the TI part might offer better performance, although it seems unlikely from the spec.So there's an exercise to figure out why the black version has three of these in place of one elantec - making it equivalent in performance, or making it better? I'd assume that better performance results in less noise in the ADC which would be interesting.If we could get a sharper picture of the bottom left corner of the board, that would be really helpful. I can't quite figure out what those other parts are. I thought they might also be 3016s, but the wiring is odd.

author: TiN
author_rank: Super Contributor
timestamp: April 01, 2020, 04:17:33 am
content: 3016C comparators + 7805 and 7905 LDOs in SOIC, since original Elantec's were powered by +/-15V.

author: voltampere
author_rank: Regular Contributor
timestamp: April 01, 2020, 06:55:48 am
content: Frank:No worries. I got your point...I tried a quick shot with a bit more resolution.Drift test is in progress.30 minutes noise does look okay...Plot is 500 samples with NPLC100.Best regardsJoerg

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 01, 2020, 07:14:08 am
content: Quote from: voltampere on April 01, 2020, 06:55:48 amHi Joerg,where did you get this A3 board from?Did KS sell it to you as a spare part, or exchange for your old board?So you dis-assemble it again for this photo?Frank

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 01, 2020, 07:16:47 am
content: Quote from: TiN on April 01, 2020, 04:17:33 amHi Illya,when will you reveal your photos of the Black Edition, and your review / characterization, or did KS not allow that?Frank

author: Kleinstein
author_rank: Super Contributor
timestamp: April 01, 2020, 07:51:40 am
content: For the comparators they use the TL3016 powered from local +-5 V. In addition they limit the input voltage range with clamping diodes and limit the input side current (looks like 2 JFETs and 3 resistors in a rather conventional circuit). The comparator is not directly connected to sensitive nodes, so the slightly higher bias should not be a problem. If at all it would be the extra current from the clamps.A different delay can have an effect as this effects the overshoot in the rundown and thus the times measured.Besides the comparator they also changed the slope amplifier. There are now 2 diode for each direction. Chances are they also changed the old relatively noisy OP.

author: voltampere
author_rank: Regular Contributor
timestamp: April 01, 2020, 09:44:10 am
content: The board is a spare part from KS germany.Story is here:https://www.eevblog.com/forum/metrology/hp-3458a-ad-board-spare-part-availibilty-and-cost/I asked for exchange to get a lower price but they denied.This shot was actually done shortly after i did the first pics with my mobile phone( the one i published before ).So " ...tried a quick shot ..." is a bit misleading here.Nevertheless is have no problems taking the board out again.It is my second 3458 that is still work in progress.I have done the basics already ( RAM upgrade, NVRAM exchange, line filter, elcetrolytics replace ).Paid more for A3 spare than for the meter itself!!! ( but i somehow expected that... ).RegardsJoerg

author: Nixfried
author_rank: Contributor
timestamp: July 03, 2020, 06:30:52 am
content: Just found two new pictures showing the innards...Look at that tiny digital board!

author: Dr. Frank
author_rank: Super Contributor
timestamp: July 03, 2020, 06:54:37 am
content: Quote from: Nixfried on July 03, 2020, 06:30:52 amIllya has a complete picture session of all PCBs on his xdevs site, but for some reason, he is stuck publishing his review any further.Just sneak in his picture folders.Frank

author: matches
author_rank: Contributor
timestamp: September 04, 2020, 03:16:52 pm
content: When I look at the specs, it seams every value one can read in the 100 Ohm range has a higher specified tolerance compared to the 1 k Range.Ppm of range is a factor of 10 higher in the 100 Ohm range and ppm of Reading is a little higher (12 compared to 10) in the 100 Ohm range.So one would be better of skipping the 100 Ohm range? Of course just pure calculation from the spec sheet.Am I missing something?

author: matches
author_rank: Contributor
timestamp: September 04, 2020, 03:18:03 pm
content: Sorry, double post

author: Kleinstein
author_rank: Super Contributor
timestamp: September 04, 2020, 05:20:45 pm
content: The ppm of range error part is mainly the offset. This offset does not improve much going from the 1 V range (1 K) to the 100 mV range (100 Ohm range) so no surprise with the fixed error / drift part.Also with voltage measurements the 100 mV range has only limited advantage over using the 1 V range - the absolute noise does not improve much, as the ADC is noise is quite good and already the 1 V range has about as much noise from the amplifier as from the ADC. Going to the 100 mV range does not help much with the amplifier noise (it helps a little with a lower impedance in the feedback network - thus a tiny bit lower noise there).The scale factor for the 100 mV range does have a little more uncertainty (one more step away from the reference). So the 100 Ohms range is of limited value, at least for slow measurements. In some aspects the 1 K range may be the better choice.With temperature sensitive resistors (e.g. RTD) even the 10 K range may be better as it uses a lower test current, that could be better for heat sensitive resistors. Other meters may have a special low power resistance more to measure 1 K with a lower test current.

author: matches
author_rank: Contributor
timestamp: September 05, 2020, 07:46:59 am
content: Ahh, now I see it. ThanksThe 100 mV range even cuts of one digit.So I could have asked the same question here.Regarding RTD measurements, that is where I noticed it.I use Pt100 together with the ‘58 as temperature reference for calibration of thermocouples.They are calibrated at 1 mA so the self heating error is included.I should make a measurement... now I’m curiousBut it’s not the big source of error anyway.

author: miro123
author_rank: Frequent Contributor
timestamp: May 04, 2022, 12:31:26 pm
content: Quote from: TiN on March 01, 2020, 05:17:58 pmHelloI'm trying to find the KS3458a review from Ilja. Where can I find it?Best regards,Miro

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: May 07, 2022, 06:13:45 am
content: Hello Voltnuts,The link below gives an impressum about the performance of the KS3458A - B.E.(Kudos: Marco Reps) ...Here is a link to TIN's article:https://xdevs.com/article/ks3458b/Herzliche Grüße/Meilleures salutations/Best regardsBest regardsScoobyDoo

author: miro123
author_rank: Frequent Contributor
timestamp: May 07, 2022, 09:19:10 am
content: Thanks for sharing.As usual Marco reps videos shows good combination of deep techncal knowledge, structured explanation and professional video processing. This 35min video is good example.

author: mendip_discovery
author_rank: Super Contributor
timestamp: May 07, 2022, 10:11:54 am
content: Quote from: miro123 on May 07, 2022, 09:19:10 amPah its 34m and 58sec (except YT had a rounding issue).

author: miro123
author_rank: Frequent Contributor
timestamp: May 07, 2022, 12:09:49 pm
content: Quote from: mendip_discovery on May 07, 2022, 10:11:54 amYoutube rounding is at least +-30 LSB based on 2160p60 video format