HP 3457A or HP 34401A? - Page 1
Forum section: electronics / testgear

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 07:10:31 am
content: So after day of research I'm down to the following options.HP 3457A or HP 34401A?The HP 34401A come with a recent calibration and NIST traceable certificate. I also got them to throw in the bumpers and stand.The HP 3457A also is a recent calibration with a NIST traceable certificate, and the calibration certificate.I have a certain appeal to the older electronics. Unlike today the washer, dryers, surround sound receivers and refrigerators die from cheap parts. Mostly the control boards, but when I was a kid the music never died, the washer and dryer just ran and no fancy control boards with digital readout a and features that sing songs. So I want to add one of these above multimeters to my bench, and I like the fact they are going to do a calibration on the one I decide to buy.As for newer DMM features like data logging, capacitance and stuff. Well I own a Fluke 289 if data logging is needed, I have the cable and full version of the software since I bought the FLV pack Fluke 289. So I'm not worried on missing a feature I may need. Between the two of them everything will be covered. The HP models will give me 6.5 / 7.5 depending on what one I purchase and the ability to do kelvins 4 wire resistance measurements.I've read the 3457A had a battery that stores the calibration, so I know I will be replacing that first.I don't know if the 34401A has a battery? The first thing to probably get replaced on the 34401A would be the vacuum displays. I also like the look of the displays on the 34401A.In the end this is a close call for me, they both are about the same price. The 34401A shows a little use, scant he's and scuffs and the 3457A is in new condition.So I guess I need to ask for your thoughts and opinions. Points like what one is likely to have more failures over time. And what one would be easier to repair and calibrate myself if it was needed. What model has more parts available and more community support?Wait, scratch the community support question, I already know the 34401A has more support, and probably more parts also since more of them sold, I think?Well any advice, comments, thoughts would be appreciated. I know I set the surgery up for 1 day, but I'll probably buy one in the next 16 hours before they close on Friday in their time zone.Thanks,Scott

author: deadlylover
author_rank: Frequent Contributor
timestamp: October 30, 2015, 07:36:35 am
content: I prefer the 34401A, it just feels easier to use for day to day tasks and it takes up less bench space too!I have both, so if you have any questions I'll try my best to answer them.edit: 34401A has no battery to worry about. And I probably reckon it'll be cheaper to calibrate later down the line should you choose to do so.

author: daqq
author_rank: Super Contributor
timestamp: October 30, 2015, 07:37:33 am
content: I'd go with the 34401A - for practical reasons mostly - it's smaller, parametically just as good. If you are thinking in terms of servicability, both rely fairly heavily on HP custom parts and I'd guess that you'll have a nasty time fixing either of them.As for the calibration, if I remember correctly the 34401A does not have a battery, the 3457A does - this might be a problem, assuming it died.QuoteNeither of them has capacitance measurement, but data logging can be done by means of the BenchVue software suite.

author: tec5c
author_rank: Frequent Contributor
timestamp: October 30, 2015, 07:51:30 am
content: 34401A

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 09:03:18 am
content: Quote from: deadlylover on October 30, 2015, 07:36:35 amYea, the no battery to worry about loosing calibration is a plus. I never looked into the cost of calibrating either one. He offered the calibration when I buy the one I choose now, and again in a year to see how it drifted (if it drifted) so that was a nice incentive to buy from him. I'm also assuming that the older DMM won't drift if they've been used more over the years and that they stable out with the burn time.Would you say either one of yours drift, maybe one more then another? How would you out the drift compared to newer feature filled touch screen DMM's these days?

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 30, 2015, 09:24:28 am
content: Hello,The 34401A has very mediocre DCI ranges!It only has two (!) current shunts, i.e. 5 Ohm for 10mA, 100mA and 0.1 Ohm for 1A, 3A.And the 5 Ohm shunt is unstable on the 100mA range, due to thermal heating, and over time.Therefore, the 3457A has much better DCI capabilities, 5 ranges and 5 different shunt resistors (0.1 Ohm .. 1kOhm) for each.That has really upset me about the 34401A, also the bad HMI, requiring many keystrokes to access basic functions, like resolution / NPLC and DCV impedance setting...for the last 22 years, when I bought the 34401A. (It's absolutely rock solid, indeed)So I really recommend the new 34465A!Frank

author: crispy_tofu
author_rank: Super Contributor
timestamp: October 30, 2015, 09:33:44 am
content: Quote from: tec5c on October 30, 2015, 07:51:30 am+1More compact, takes up less space!

author: deadlylover
author_rank: Frequent Contributor
timestamp: October 30, 2015, 09:37:52 am
content: Quote from: Scottjd on October 30, 2015, 09:03:18 amNothing much between them, they both use the LM399 voltage reference IIRC. Ditto with the newer 6.5 digit meters except the Keysight 34470A or Keithley 7510.I wouldn't worry about the drift at all, it's not something I would think about when picking between the two.The 34401A being more modern, and having higher ranges like 1000V DC or 3A DC (though its kinda poopy like Dr. Frank said) would easily push me towards the 34401A over the 3457A. I much prefer a VFD over the LCD on the 3457A too.

author: lowimpedance
author_rank: Super Contributor
timestamp: October 30, 2015, 09:46:52 am
content: The 34401 VFD do fade with use , but I guess for home lab use it should not be a real issue. And there are plenty more 34401's around than the 3457a so spares would be easy to source.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 11:45:51 am
content: Quote from: Dr. Frank on October 30, 2015, 09:24:28 amThanks for the heads up on the shunts Frank.For my current needs I usually turn to my Fluke 289. Mostly because my LED flashlight projects tend to pull more then 3A on a single 18650 cell. It's the way I make the drivers since I know I cover the thermal dissipation for the LED heat to handle running the LED at full.Also, when I first bought the 289 I decided to buy spare fuses since I didn't own any bus fuses. It's easy to under estimate the current or for me have the driver programmed wrong and end up on mA, then pull more them 400mA. Sometimes it's testing and fixing someone else's light. So I bought a 5 pack of fused for the mA, and 2 fuses for the 10A side (but takes an 11A fuse and can do 20A up to 30 seconds)So instead of taking a chance on damaging an older meter I'll probably stick to the fluke for current readings.Buts it's good to know about the shunts, so if any of my mA references show up out of spec if I get the 34401A, at least I'll probably know the reason why.Thanks.

author: bingo600
author_rank: Super Contributor
timestamp: October 30, 2015, 01:54:48 pm
content: I have both , and use the 3457 for "logging" , and the 34401 for "normal use".If i should select just one , i'd take the 34401/Bingo

author: kfnight
author_rank: Regular Contributor
timestamp: October 30, 2015, 03:07:54 pm
content: I've always preferred the larger (more buttons) front panel layout of the 3457A compared to DMMs with less buttons, since less buttons means more menus to wade through to do simple things like averaging and statistics.

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 30, 2015, 03:55:43 pm
content: I don't own a 3457A, but on a 2nd thought, and a read into the manual, I really would prefer it over the 34401A!It really has all the modes on the first layer of keys, so DCI, ACI is one key press, instead of 2nd / shift function like on the 34401A.Then it has very precise OHM functionality, OFFSET Compensation, which only few system DMMs have.Not to mention all the mathematical functions, and that nice numerical keyboard for entering values, instead of clumsily increasing/decreasing each digit by the up/down arrow keys.Oh yes, and if this 3457A includes a scanner card, preferably the 44491A, then it's a no-brainer.. that's a real DMM- and function-multiplier, 8 DMMs in one, or so!I'm a real fan of scanning in a measurement setup.Frank

author: lukier
author_rank: Unknown
timestamp: October 30, 2015, 05:09:37 pm
content: And 3457A has quite good 24h accuracy on 3V range - ~5ppm AFAIR. Not many other meters, even 7.5 digit ones are that accurate (e.g. new 34470A = 10ppm, Keithley 2001 on 2V range - 9 ppm).I use Keithley 2015 for everyday work (pretty much the same specs as 34401A). Fast, has continuity, decent accuracy, but I've ordered 3457A for more precise measurements, low current ranges and logging.It's a pity that 3457A cards are difficult to find / expensive. I wonder if some 3488A cards could be modified.The schematic for 44491A is fairly simple. Quality relays might be a bit expensive, but in general it should be possible to DIY 44491A replacement.

author: HighVoltage
author_rank: Super Contributor
timestamp: October 30, 2015, 06:07:25 pm
content: I never owned a 3457A but I have several 34401As and they are all just perfectly performing.My oldest one is probably from 1994 and the newest one is Keysight branded.The difference between to oldest one and the newest one is tiny, when comparing calibration offsets.I have also installed several 34401A meters in production environments and they just always work.And since you mentioned data logging, it is also very easy with the 34401A, if you ever want to start that route.

author: SharpEars
author_rank: Unknown
timestamp: October 30, 2015, 06:13:56 pm
content: Quote from: HighVoltage on October 30, 2015, 06:07:25 pmI can tell you this, the newer ones drift much more on the voltage ranges than the older ones, even among just HP units.

author: wraper
author_rank: Unknown
timestamp: October 30, 2015, 06:26:26 pm
content: Quote from: SharpEars on October 30, 2015, 06:13:56 pmAFAIK this is just different default setting in the newer firmware because of which it looks like measured value is less stable. Free Electron mentioned this in some tread.

author: bingo600
author_rank: Super Contributor
timestamp: October 30, 2015, 07:32:19 pm
content: Have a look herehttps://www.eevblog.com/forum/testgear/is-my-'new'-fluke-731b-stabilizing-or-going-crazy/msg779636/#msg779636And some measurements where i use both the 3457 & 3458https://www.eevblog.com/forum/testgear/is-my-'new'-fluke-731b-stabilizing-or-going-crazy/?action=dlattach;attach=176875I am using the HIRES register of the 3457 (7.5 digits) bit not making multipple samples.So this is what a 7.5 dig looks like on a "one off sample"/BingoEdit: I have a scanner card in my 3457

author: SharpEars
author_rank: Unknown
timestamp: October 30, 2015, 07:37:27 pm
content: Quote from: wraper on October 30, 2015, 06:26:26 pmBut both of my newer units are almost 20 PPM off at the 10 V setting.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 07:44:00 pm
content: Quote from: Dr. Frank on October 30, 2015, 03:55:43 pmYes, I wish. If it had the scanning card I probably wouldn't have started this thread. But no, it does not have any options or cards installed.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 08:17:54 pm
content: Quote from: lukier on October 30, 2015, 05:09:37 pmThe Keithley 2015 was in my initial list, found one for about $500 US on eBay. I think it got crossed off when I figured out parts are more expensive, harder to troubleshoot and calibrate, and most used 2015 are going for about $1,500. So the low price threw up a red flag also since it was a "Get what you pay for, no warranty" buy. Still a nice meter. I watched Daves tear down of it and was impressed with the thought behind some of the design.

author: SharpEars
author_rank: Unknown
timestamp: October 30, 2015, 08:51:09 pm
content: Quote from: Scottjd on October 30, 2015, 08:17:54 pmYes but what about its noise footprint vs the 34401A (i.e., deviation in reading over time)?

author: deadlylover
author_rank: Frequent Contributor
timestamp: October 30, 2015, 10:32:19 pm
content: Well, I think the solution is to just get both...eventually.If you plan on doing any data logging, the 34401A can output via RS-232 or GPIB whereas the 3457A only has GPIB. Cheap GPIB to USB cables start at ~$60 or so for the clones, not too insignificant IMO.I mainly use bench meters like I would a handheld meter, hence I prefer the 34401A, it feels like a really nice handheld. But I think you could probably have a fair bit more 'fun' with the 3457A. Listen to your heart, they're both fine machines.

author: lukier
author_rank: Unknown
timestamp: October 30, 2015, 10:36:27 pm
content: Quote from: bingo600 on October 30, 2015, 07:32:19 pmGreat jobSo it seems that 3457A peak-peak variation over these periods is around 40uV and 3458A, as expected, is around 10x better - exactly as in the specs. The important thing for me was that I scored my 3457A for $95 and I would never find 3458A for 10x the priceI think it is hard to beat 3457A in price/performance ratio.Do you have the raw data somewhere? I would be interested to see shorter range, something like 5-10 min to see transfer accuracy and noise of both 3457A and 3458A. Maybe it does make sense to build triple LM399 reference board, as TiN showed in recent 3456A thread, to reduce the noise.

author: lukier
author_rank: Unknown
timestamp: October 30, 2015, 10:41:06 pm
content: Quote from: Scottjd on October 30, 2015, 08:17:54 pmThis is the rare situation where some gear seems to be more affordable and available in the EU (normally eBay USA rules)I got my 2015 over a year ago for 250 GBP and the same seller still sells them at this price. From what I've heard (not sure if it's true) recent surplus of Keithley 2015 or Agilent 6632B is due to Nokia closing the mobile phone division in Europe (after selling it to Microsoft) some time ago.It is a very nice meter, super fast, and as someone said above "feels like a nice handheld", but I wouldn't classify it in the volt-nut category

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 11:11:31 pm
content: I wanted to thank everyone for the great information. Even after days of obsessive research and reading all the posts on EEVBlog about the meters this thread still produced other relevant information that I didn't run across. It's just amazes me with the amount of combined talent that posts on the EEVBlog.Everyone had made some great points to take in consideration. I decided to get the 34401A, but yes the goal would be to have both or even maybe a 3458A in the future if I can get it for a good cost.For now I think the 34401A will compliment my current lab equipment as a hobbiest.I ended up putting a best offer bid in for $50 less with stand, bumpers, NIST trace cert, calibration and they accepted. So recent calibration, NIST traceable cert, and I ended up paying another $50 for the calibration data showing me what needed to be adjusted and by how much so I have a starting point reference when I send it back next year for the re-cal and re-cert.Sending back in next year is included in the price, I just pay shipping then I will see by how much if drifts if it does at all.So in the end it may be a little more then some you can find as a bargain price, but I know is calibrated and fully tested and get another calibration next year for the final price of $450 + $50 for calibration data.I spoke with the technician that will be calibrating it, had a great conversation. He then asked if I wanted the HP labeled one or the Agilent labeled one. Since the Agilent started it labeling on this meter about 10 years ago he said the most stable ones are going to be the 15yr old units. He was explaining how the resistors can drift/sway back and forth each 1.5yrs. This can go on for 8 to 10 times before they settle 100%, so over 15yrs it would be the most stable version to get an HP labeled one.So I'm pretty sure he will be sending the HP labeled one, but he said he will send the best one for what I had purchases it for. He had some great information to also take into consideration.I will definitely be buying more stuff from them in the future. They have a lot of stuff to look at and also do a lot of walk in buisness from what I understand.Thanks again for everyone input. I'll update the thread once I receive it next week.ScottIf anyone else is interested this is the link to the eBay store.http://www.ebay.com/sch/teletek23/m.html?item=400249303415&ssPageName=STRK%3AMEBIDX%3AIT&rt=nc&_trksid=p2047675.l2562Looks like they still have a couple more 34401A left also.http://www.ebay.com/itm/400249303415?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 30, 2015, 11:14:43 pm
content: Quote from: deadlylover on October 30, 2015, 10:32:19 pmYes, I believe that is the future plan.I've also decided to just let the poll expire at the set time since it was set for 24 hours. It's still interesting to see the results when it does finalize and people comments. Seems like the thread is taking on a persona of its own.

author: eas
author_rank: Frequent Contributor
timestamp: October 30, 2015, 11:21:32 pm
content: Quote from: Scottjd on October 30, 2015, 08:17:54 pmWhat? That's not right!Don't look at the asking prices of active listings. They are going to be heavily biased to show the price at which things DON"T sell. Look at the price of recent sold listings. A Keithley 2015 for $500 is by no means an outlier. It might actually be a little bit high.

author: lukier
author_rank: Unknown
timestamp: October 30, 2015, 11:25:47 pm
content: Normally I don't trust ebay sellers that much when they say they checked the item or mention NIST calibration, but this seller seems experienced in T&M area, sold over 130 of these meters and the technician is roughly right about the drift. If you are going with the old HP one maybe ask how much they refurbish them, maybe electrolytic caps should be replaced? (dunno about 34401A but leaking caps plague old Keithley meters). If the caps are ok then the meter will serve you many many years until the VFD fadesIt may not be the purchase to post in the "what you scored" thread, but it seems that you got good deal overall, with all the bumpers, in good condition, calibration data and next year calibration included. In a year you'll have very good confidence with this meter - not something I have by hunting for scores from random liquidation sales

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 01:53:51 am
content: Quote from: eas on October 30, 2015, 11:21:32 pm

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 02:02:08 am
content: Quote from: lukier on October 30, 2015, 11:25:47 pmYea, I have to say my confidence in the seller went up after talking with the technician. And the sales conversation I had yesterday with the girl that answered the phone. I did search for their main website also, according to the site they have been in buisness for 30 yrs.oh, and they told me if something is repaired from their techs then it's listed as refurbished by owner.But they also said they have enough walk ins that it's not usually worth repairing most items, so they have another eBay store for selling parts and broken things for parts.They even sold one 34401A yesterday with the Ohms feature broken for $250. I guess if you don't need that part then, well...... He even told me one 34401A came back three times. They lost it for $470 and it says AC does not work. But people buy it, then return it saying AC didn't work. I guess they don't read the ad writing in eBay listings.I don't know, I would rather know the whole meter works. You never know what's caused the Ohm or the AC reading part of the meter to fail. Took a surge? Will other parts fail in a few months from slight damage from a surge? To many risks with a partial working meter, ice rather not buy one like that.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 04:57:09 am
content: Quote from: Dr. Frank on October 30, 2015, 03:55:43 pmI just wanted to let you know I was reading the HP 34401A manual and found this in chapter 7, page 214.Is this the same offset compensation you were talking about being on the 3457A?Making High-Speed DC and Resistance MeasurementsThe multimeter incorporates an automatic zero measurement procedure (autozero) to eliminate internal thermal EMF and bias current errors. Each measurement actually consists of a measurement of the input terminals followed by a measurement of the internal offset voltage.The internal offset voltage error is subtracted from the input for improved accuracy. This compensates for offset voltage changes due to temperature. For maximum reading speed, turn autozero off. This will more than double your reading speeds for dc voltage, resistance, and dc current functions. Autozero does not apply to other measurement functions.

author: bitseeker
author_rank: Super Contributor
timestamp: October 31, 2015, 05:32:17 am
content: Quote from: Scottjd on October 31, 2015, 02:02:08 amYeah, I've seen those listings. The confusing thing about them is that they're listed as NIST calibrated, but part of them doesn't work. Although they do say what doesn't work and list them as "for parts, not working", it's rather unusual to effectively be saying, "it's well within specifications according to our NIST calibrator...except for the part that's broken, of course." I don't know about others, but my expectation is that a device with a cert is fully functional. As always, caveat emptor.Let us know how you like the 34401A when you receive yours.

author: bingo600
author_rank: Super Contributor
timestamp: October 31, 2015, 06:21:23 am
content: Quote from: lukier on October 30, 2015, 10:36:27 pmI'll dig it up during next week , not @home right now/Bingo

author: bingo600
author_rank: Super Contributor
timestamp: October 31, 2015, 06:44:38 am
content: Quote from: lukier on October 30, 2015, 10:36:27 pmThat's a great price for a 3457 , i think i payed $240 for mine , with a scannercard though.And £280 for a K2015 (KJDS)The 34401A was new in Box, just used a few hr's. I payed around $450The 3458A Opt002 (Outchh) .....I got to know a CalGuy , and got my 3478A,3457A and 34401A Cal'ed for $120.That's not a bad deal.Unfortunately he can't Cal my 3458 , as he hasn't got the right equip. in the division he's in , that one had to go in "official @ $$$$$"/Bingo

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 31, 2015, 08:47:51 am
content: Quote from: Scottjd on October 31, 2015, 04:57:09 amNo!AUTOZERO only removes any DC offsets of the DMMs internal OpAMPs and thermal offsets inside the instrument . This applies to all modes of the DMM.The OFFSET COMPENSATION function only applies to Ohm mode, either 2W or 4W mode.The DMM first switches off its internal current source and measures the residual voltage, caused by the DUT, and also by its internal OpAmps. (Therefore, Autozero is not used in this case)Then it measures the voltage with the current source switched on, and calculates the difference between both measurements.So this function also removes thermal voltages from the DUT.This improves the accuracy, especially when the thermo voltages are on the order of the resistance changes to be measured, as with PT100 thermometers.This feature is very rare on DMMs, and can be found on high grade system DMMs only.Frank

author: lukaq
author_rank: Regular Contributor
timestamp: October 31, 2015, 11:54:45 am
content: if you are coming from the world of using handheld DMM, any of those two will be big step up. I would and did go for 34401. As far as VFD goes, depends on its use it had, my looks as "new". Small DMM, really love using it. Like everything, it has its good and bad things, but for me, more good than bad.

author: KJDS
author_rank: Super Contributor
timestamp: October 31, 2015, 12:25:59 pm
content: For anyone in the UK or EU after a 6.5 digit meter, I've got working 2015THD, 34401a and solartron 7150+ in stock.

author: 3roomlab
author_rank: Frequent Contributor
timestamp: October 31, 2015, 03:37:17 pm
content: Quote from: eas on October 30, 2015, 11:21:32 pmeas is right. i got mine for approx USD350 shippedbut i was off my usual hunting and i just grabbed it. the unit is last cal 2007. except for a crazy noise problem on the low NPLC range i am trying to figure out, i think it is very usable. then again, it is ebay, anything can happen, a cap might just go poop.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 06:34:23 pm
content: Quote from: Dr. Frank on October 31, 2015, 08:47:51 amOk, got it. Now that's neat.I'll have to get the manual for the HP 3458A and see if this one also does that feature.I was reading up on the 3458A, the auto calibration is nice with the internal voltage/current reference. The IC used on the reference board are very good, I was reading the data sheets to see what reference chips and amps were being used and why the voltage ref board sells for $300 to $450 even used. Now I know why. The one chip alone is $56.This is a nice meter, it's now on my lift of things to buy going forward and it may have already moved to the top of the list. But this one will be a search and find the best deal possible eBay buy because of the price, unlike the one I just bought.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 06:50:58 pm
content: Quote from: bingo600 on October 31, 2015, 06:44:38 amDoes the 3440A track hours in use? I know the 3457/58 does?I'm still reading over the manual, but it's 254 pages long. I found it amazing the level of errors it reports/checks on the self test for being made so long ago. I think the 34401 was ahead of its time and I'm staring to understand why it's referred as a "standard".The service manual (also reading that) refers to some serial number ranges were changes should or was made. If I knew this ahead of time I would asked for the Agilent labeled one to ensure these changes were made, oh well. It shipped out today so to late.One is having to do with the display board, that might explain the very few videos on YouTube with a display issue just flashing when it starts up. But when I was searching I couldn't find that many people noting problems with them considering how long they have been making them. It's really quite impressive if you think about it.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 06:56:24 pm
content: Quote from: lukaq on October 31, 2015, 11:54:45 amYup, my fist bench DMM. After years of replacing handheld ones ever couple of years at $60-$100 I finally justified buying a fluke handheld for the 10yr warranty. So o got the 289 FLV pack one.So now I decided to get my first a bench one.

author: bitseeker
author_rank: Super Contributor
timestamp: October 31, 2015, 07:06:43 pm
content: I believe what you're referring to about the display is that there are two models of the front panel board and controller. They are not interchangeable. So, depending on which one you have and the associated mainboard firmware version, if you ever have to replace the front panel board, be sure to get the same model.More info:http://cp.literature.agilent.com/litweb/pdf/34401A-06.pdfHowever, this compatibility restriction does not apply to the VFD module. All 34401A use the same VFD module, so when yours dims beyond an acceptable level, you can get a new VFD and rework your existing PCB to install it.

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 31, 2015, 08:04:20 pm
content: Quote from: Scottjd on October 31, 2015, 06:34:23 pmYou don't have to read the manual, I can tell you, that the 3458A definitely has this Offset Compensation function.Of course, I'd say, as this instrument is still one of the top notch 8 1/2 digits DMMs.It's absolutely desirable, as you also buy a complete calibration laboratory, by its unique AUTOCAL feature. Please read about that in the hp journal April 1989.The voltage reference is expensive, only due to the selection process, HP had to perform on it.From the BOM only, the board is much too expensive.Much more stable reference boards with the LTZ1000 can be built DIY by appropriate selection of external components, and especially a lower oven temperature. See discussion in the "Ultra LTZ1000 reference" thread.This instrument otherwise does not have ultra stable components inside, (compared to e.g. the Fluke 8508A). It's accuracy and stability on all ranges is derived from the stable volt and ohm references and the worlds best-linear analog ADC inside.Ah yes, neither the 3458A, nor the 34401A have RTCs inside to measure the on-time, etc., and I really doubt that the 3457A has that feature.Only the new TrueVolt DMMs like the 34465A log different time periods.Frank

author: cncjerry
author_rank: Unknown
timestamp: October 31, 2015, 08:19:36 pm
content: I bought two 3457a meters at different times for less than $150USD per, both with scanners, off craigs list in the SF Bay Area. I haven't seen a 34401 at that price point in really good condition. Both had old calibration but were very close to where it could have been noise at the time of comparison. I've found that shielded leads make all the difference in accurate readings, duh, so I would allocate money for good quality leads.I did some ADC testing as in the long thread a while back and couldn't believe how flat the meters were when using the HIRES register over GPIB. Also, the statistics are easy to use if you need a really accurate comparison for low level resistance when checking current sense, for example.I don't have experience with the 34401, but the 3457a is very easy to calibrate if you have standards.The funny thing though is that my 3456a meters seem just as stable at 6 digits. So when sorting .1% resistors I use a 3456a first.

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 09:22:33 pm
content: Quote from: Dr. Frank on October 31, 2015, 08:04:20 pmYes, the auto cal is nice, I'll have to read the HP April journal now.Thanks for the tip on the Ultra LTZ1000 thread, I'll search it out. I'm looking to build a reference next, I saw the data sheet had specs for one when I looked up the part numbers on the 34578A voltage reference board. That's how I ended up down that road. But I'm still researching for the best BOM to accuracy cost for building one.The RTC comment was based on a MJLorton video when he bought one and stated it only had 50 hours logged on it. So maybe it does, or he may have made a mistake?

author: Scottjd
author_rank: Frequent Contributor
timestamp: October 31, 2015, 09:33:40 pm
content: Quote from: cncjerry on October 31, 2015, 08:19:36 pmYea, their is a big difference in Craigslist East Bay SF and Columbus. I miss the Bay Area, lived their for 18 years until taking a job transfer at the bottom of the economy 8 years ago to Columbus. I'll be back in Pleasanton/Fremont area either in November or December. You think they will let me do a 3458A as my carry on luggage?New probe already on order, so I should be getting the meter and probes about the same time, with a set of kelvin probes also now that I can do 4 wire. The last thing I'm looking for is a GPIB to USB, or one of the combinations that work to the computer.I have a serial to USB for the MacBook Por, but I think I read it doesn't work and needs a special converter box for GPIB to CPU. OS and software shouldn't be an issue. I run a lunix, Windows 10 tablet, MacBook Pro, and Windows 7 virtually on MBP. So options for software or she'll scripting are open if I get the correct converting box that supports drivers for hopefully the Mac, or lunix host.No standards, but the shop I bought from would have calibrated before shipping, then again calibrated included in the cost next year, I just pay shipping to them. I figured 2 years would have given me enough time to build up more of the lab and buy some standards.

author: lukier
author_rank: Unknown
timestamp: October 31, 2015, 10:55:58 pm
content: Quote from: Scottjd on October 31, 2015, 09:22:33 pmTried to watch these videos, but man, I cannot stand his monotonous delivery. That is not the biggest issue with his videos though. Managed to watch maybe 50% of both installments on 3457A and it wouldn't surprise me if there was a mistake there. There were so many inaccuracies, factual errors and bad practices that I stopped watching. I understand that mistakes happen (especially in a non-scripted recording) and everyone makes a goof of himself once in a while, but here it was just too much - it is just spreading misinformation, worse than no video at all. A bit disappointing for someone that want's to be a pro multimeter reviewer. I remember reading even harshest comments on these 3457A videos on the volt-nut mailing list.As bad as the videos are I don't think he was mentioning on-time (thus implying RTC that 3457A doesn't have), but calibration counter. He thought that the meter received 34 full calibrations, but in fact (as the manual says) the counter counts every calibration point separately therefore his meter was probably calibrated just once in its lifetimeSome multimeters allow to enter the calibration and due date (manually) to be stored in the non-volatile memory. I know this is the case for Keithley 2015, not sure about 34401A or 3457A.Side note: 3457A is quite peculiar when it comes to the front end. There is no range that goes straight to the ADC (like 10V does on most multimeters). Here even the 3V range goes through the input amplifier (3.33x) to be amplified to 10V for the ADC. 30V range goes through 1/100 divider (that is normally used for high voltage) and then again to the amplifier. This is very strange and not very volt-nut friendly as the usual 10V reference standard would fall into this divider-amplifier path that has worse performance and also it doesn't have GOhm input impedance on this range as wellI wonder why HP decided to design the front end like that, anyone would hazard a guess?

author: eas
author_rank: Frequent Contributor
timestamp: October 31, 2015, 11:19:14 pm
content: Quote from: Scottjd on October 31, 2015, 06:34:23 pmIt is a very nice meter in some ways, and I guess if you can afford one, and you want one, why not buy one? Just understand that unless you have unusual needs, you are basically buying a Formula 1 car for occasional trips to the supermarket down the street. Actually, that's not true. The 3458a is going to need a lot less maintenance than an F1 car. Even so, consider what the point of having that sort of precision and accuracy is if you can't be confident it it, and consider what it costs every year to have piece of mind that the high-end instrument you spent thousands on, which takes up a huge patch of bench/shelf space is providing the capability that attracted you to it in the first place.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 01, 2015, 01:06:24 am
content: Quote from: lukier on October 31, 2015, 10:55:58 pmThat is possible. I did read that in the service manual last night and made a note to check the 34401A when it arrives. I also noted a full calibration is 34 counts. But also given the age of some of these I have to remover the counter does roll over back to zero so it may never be possible to know for sure if it was in an environment that had it calibrated ever 90 days, for many years. Then sold off.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 01, 2015, 01:17:34 am
content: Quote from: eas on October 31, 2015, 11:19:14 pmAgreed, but I like to drive fast also and this won't eat up as much money in gas. :-)Seriously, I fully understand what your saying and I use that kind of logic with almost everything I buy.No, I'm not rich. Not that I know of anyway.But I do maintain a YouTube channel I'm trying to get off the ground, and I think the theme is moving to the hobbiest cheaper side of things. Like a 1054Z instead of one that costs 3K to start.Or the $28 voltage reference and not the $130.The SMD rework station is a $150 Aoyue, not the $1500 starting one.So something that most average people can still buy.So I guess the point of a meter like that would be to show people that the $29 voltage reference is, or isn't worth buying. They sell these things and mark them with the measure Kent take from a 6.5 bench meter, but who is to say that meter is even accurate. At least if I scored a good priced 8.5 accurate calibrated meter I would be able to prove some of these questions and fact.It's not on the immediate list, more like let's wait and see how much I get on my tax return this year. The one time of the year I spurge on a bigger item for being a good boy and not having any credit card debt, or car payment and so on, Just a mortgage.Again, this all depends on if I even run across one in eBay for a price that I like. It will be a "Wait and see if I can score" buy.

author: deadlylover
author_rank: Frequent Contributor
timestamp: November 01, 2015, 02:35:17 am
content: Quote from: Scottjd on November 01, 2015, 01:06:24 amRemember, calibration =/= adjustment, I wonder if there are any 34401A's out there that has been adjusted over 32767 times to have the cal count roll over.For what it's worth, I have a 34401A that hasn't ever been adjusted since 1996 when it left the factory, and most of its ranges are still within 1 year spec. Hell, 10VDC was still in 90 day spec IIRC.If you're after acheapless expensive 8.5digit meter, keep an eye out for the Advantest R6581. It's kind of like a baby 3458A as it is capable of 2 source artefact calibration and thus auto calibration. As a small bonus, the reference inside isn't as abused as the 3458A, so its 10VDC spec is 5ppm vs 8ppm of the normal 3458A model.The battery inside the R6581 holds the auto calibration memory, and without it, the meter auto ranges like a madman with relays firing non stop, not to mention the meter won't show any readings. The meter self tests on power up but it will only display the error annunciator for the first power cycle in which the battery dies.The combination of these things will make the seller list the meter for very cheaply, my first used 34401A cost more than the R6581...My battery was dated Feb-1998, there must be other units running out too, so I hope this helps someone snag a fantastic deal. I do think the R6581 is a hidden gem, sure, it's not as good as the legendary 3458A but it'snearlyas good as one, and praise doesn't get much higher than that I suppose. I wouldn't pay >$1000 for one because that's creeping on 3458A territory, but at 3-digit pricing it becomes one of those things you can'tnotbuy.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 01, 2015, 04:29:29 am
content: Quote from: deadlylover on November 01, 2015, 02:35:17 amI guess not. If a full calibration (34) was done every 90 days since it was released in 1992. Over 23 years it would be calibrated about 93 time, so the counter would say 3,171. LOLIt has a long time to go before it rolls over. I just remembered reading that it does roll over, but didn't remember the number. So if it's over 3,000 then it was probably repaired A LOT.

author: eas
author_rank: Frequent Contributor
timestamp: November 01, 2015, 04:39:19 am
content: Quote from: Scottjd on November 01, 2015, 01:17:34 amI got curious about 3458a prices a few months ago when a lot of damaged units showed up on Ebay. Units with serious issues can go for over $1000. A working unit can go from $3500-5500, depending on options, condition, and recentness of calibration. Keysight will fix and do a basic calibration on a malfunctioning, but complete, unit for something like $2,900. Their lowest tier calibration is $615.There are a few high-volume liquidators who have sold a small number of 3458a's for $1000-$1500 each in the last six months or so. My guess is that they probably worked, since the seller reports things like whether the unit powered on, and whether it displayed any error messages, but the calibration wouldn't have been up to date. They all sold within an hour or two of being listed. Another deal like that should come along any month now. Maybe you'll be the lucky one!As for YouTube showmanship, that's your creative decisionI will say though that I don't think independent verification with a 3458a is really going to shed too much light on the question of whether those $15-30 eBay voltage references are worth buying because you can already reason most of it out.First, what would make them worth buying? We can be sure right up front that they aren't good enough to calibrate the 10v range of a 6.5 digit meter to factory specs, because, at the very least, they'd need to provide ~another digit of precision in the readings, and the user would need to be confident in their long-term stability. They might be suitable for calibration of a <=5.5 digit DMM though. They'd also be somewhat useful for verifying that a 6.5 digit DMM isn't horribly out of spec.Second, would a review using a 3458a provide definitive information about their utility for the above purposes? Not really. They still won't be useful for calibrating 6.5 digit meters. You might cast doubt on their utility for calibrating 5.5 digit meters and verifying 6.5 digit meters, but that's pretty unlikely because chances are, the 6.5 digit meters used to provide the actual values are likely to be accurate to within their one year tolerances, and if they weren't someone would have noticed by now, and posted about it, in english, on the Internet somewhere, perhaps this very forum. Conversely, you you might add confidence, but either way, you'd need to measure a large enough sample size to achieve significant predictive power.On the other hand, if you get a decent price, you can always sell it when you are done with it and break even.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 01, 2015, 08:51:16 am
content: Well I wouldn't ever recommend or say any of the cheaper references would,be good for calibrating .Even based off the specs for most of the AD packages they use most will drift to much.But I do want to make some of my own refernces as well. And it seems as voltage reference chips go they are getting better and cheaper even for the 1ppm chips. So who knows, maybe someone will come out with a design to meet qualifications for calibration and stay low cost.As for sampling, I have 4 of them now just because they were given to me cheap. I think all four together might have cost $30. I have my 289 logging one, and they've all been plugged in for a week so far. I'm just curious like that I guess.Well back to test lead hunting.I thought I had a good manufacturer but they don't make any sheilded leads.I'm leaning towards the Pomona 6303. They are shielded and use the 4 wire kelvin in a unique way with a solid tip on the probes. Not a bad price either. They are restricted for a max of 30V, but I don't see going over 30 unless I'm working on a house mains. Even the I would use the portable handheld fluke.Has anyone tried these leads? Or maybe have any other recommendations on sheilded leads?I was going to buy a sheilded set, then another 4 wire set. This seems to combine both into one.http://www.tequipment.net/Pomona6303.asp?OrderItemId=3181630

author: HighVoltage
author_rank: Super Contributor
timestamp: November 03, 2015, 04:42:18 pm
content: Just for fun, I compared my oldest 34401A from 1994 with my newest 34401A (Keysight branded from 12/2014)This reading is after about 6 hours on the voltage standardThe older 34401A was last calibrated by a lab in 2000.It is kind of amazing to me, how stable these meters are.

author: bitseeker
author_rank: Super Contributor
timestamp: November 03, 2015, 05:11:43 pm
content: That's excellent. Thanks for the real-world longevity comparison.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 03, 2015, 06:18:03 pm
content: Here are some more real world comparisonsNow on my Clarke-Hess Voltage SourceAnd as a reference shown with the new 34470AFirst pictures 1000V DCIt seems the older 34401A had a good drift or it was not calibrated in this value in 2000After that, we see the AC comparison at 50 HzAstonishing, how close the newer Keysight branded 34401A is to the 34470AIf someone is interested in 400 Hz AC comparisons, let me know, as the Clarke-Hess is offering different frequencies

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 04, 2015, 08:15:59 am
content: Quote from: HighVoltage on November 03, 2015, 06:18:03 pmThose are great comparisons, I would guess maybe the HP wasn't calibrated in that range as you already suspected.Well when I bought mine (don't have it yet) I laid a little extra data and explained it to the tech.Basically all 5 they had in stock had old calibration stickers on them noting the date.So I asked for the old date sticker. New calibration (included in price) and extra dating showing the original readings from the old calibration before making any new calibration adjustments. It was more out of curiosity to see how much the one I bough had drifted from the last calibration. And I'll track that data again and compare it to next years calibration.It should be interesting to see how stable or not stable on the one they calibrate and send to me.Thanks for providing those pics and taking those measurements......

author: tec5c
author_rank: Frequent Contributor
timestamp: November 04, 2015, 08:39:38 am
content: Quote from: Scottjd on November 01, 2015, 01:17:34 amName of the channel?

author: SharpEars
author_rank: Unknown
timestamp: November 04, 2015, 05:26:32 pm
content: Quote from: Scottjd on November 01, 2015, 01:17:34 amQuote from: tec5c on November 04, 2015, 08:39:38 amCount me in, I want to watch too - what's the channel?

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 04, 2015, 11:33:32 pm
content: Quote from: SharpEars on November 04, 2015, 05:26:32 pmI'm not ignoring you guys, I promise. But I have to explain something first before I post this channel.I originally created a gmail account years ago before I ever saw Daves EEVBlog channel for things like software bundles that required you give them your email, but I didn't want the spam. Back then a gmail account automatically came with a YouTube account. This is when it was a common thing for sites to sell your email address, even valid site you buy stuff from. Turns out Direct TV does this also still today, so I guess it's just something to accept and spam filters are better now days.It just happens that the channels name is Dave B. So I've been trying not to post it in the forum as to not offend Dave Jones. I'm working on changing the names on these accounts and I'm ironing out the bug and doing the do diligence to make sure this won't affect the few subscribers I do have. I also have a 3D print channel for Makerbot Replicator 2 upgrades, and a diabetic support channel. So at first I thought it would be good to keep these channels separate before realizing people might think I'm trying to get subscribers using the same name as Dave.If I can work with Google to combine and move the videos to the 3D channel and rename that one I think it would be the best. But YouTube-Google does not make this easy. And I don't believe I should be forced to use my full name on social media sites. This was a bigger concern given my profession when I was working, not so much now.It will never be a Dave channel, I'm more in the side to cheaper tools I guess for what I can afford and plan to also do general gadget reviews since I've always been a gadget tech guy. Also with my health I may not post a new video for weeks, but then I may have a good day and post 5 the same week. It's easy to shoot a video, it's the existing and checking fact that takes time.So the name of the channel, or videos may even move to another channel. Just a heads up so you know. I'll post the 3D replicator channel also since they may combine, this way if you subscribe to both and of i delete the Dabe channel name one you will still know about new videos if you select to be notified in the subscription settings. Still trying the to decide the best way to change this around.It was also pointed out to me that my 3D channel name can be viewed two different ways.It was supposed to be "Mr. ScottJD"But can also be viewed "Mrs. CottJD" - as in a female, lol.So I guess I don't make good decisions when it comes to naming channels.I hope that all made sense.Thanks, ScottGadget Tech Channelhttps://www.youtube.com/channel/UCq4qw9Rj_AebpIpari5wx9w?view_as=public3D replicator upgrade channel:https://www.youtube.com/user/MrScottJD

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 05, 2015, 01:12:04 am
content: So when researching the GPIB to USB I was reading some mixed results on some of the available adapters..I was shocked that keysight wanted over $550 for it. I found some at $50 and others around $80.I wanted to make sure The keysight software works with it also. After some searching I managed to find a eBay listing for a little over $100, the little extra seemed worth it to ensure everything would work and compatibility. I've never did a eBay return so with forgeries becoming more common on popular electronics I didn't want to risk it. The. I found the same guy had them listed on Amazon and as prime for the same price. I've been able to return fake items to Amazon without a hassle so it seems it was less risk.If I knew keysight wanted $550 for this adapter I would have bought a new one that has USB built in, but then may loose the stability I was looking for with a used one already burned in with hours of use.Well I got it today. As far as I can tell it looks like the real thing. Bran new, sealed in box with matching serial numbers on the box. Just need to get the DMM in the mail and I'll be able to test.

author: deadlylover
author_rank: Frequent Contributor
timestamp: November 05, 2015, 01:46:54 am
content: Hate to break it to ya, but there's a chance that particular one might be counterfeit. (yeah, who'd counterfeit GPIB-USB adapters, right? =P)There's a thread about ithere.Check the warranty status on the Keysight website, if it points to 2009 then it's prooobably a fake IIRC. You'd know for sure if you open it up, but I think you'd want to avoid that to prevent any hassle for returns. It'll probably function just fine though, but who knows for how long.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 05, 2015, 01:18:43 pm
content: Quote from: deadlylover on November 05, 2015, 01:46:54 amJup, most likely a counterfeit.Measure how deep the 8 holes are from the inner circle of the Agilent logo of the plastic housing.On the real one they are 0.94 to 0.99 mm deep.The counterfeit one (I used to have) had only about half of that.

author: bson
author_rank: Unknown
timestamp: November 05, 2015, 05:54:58 pm
content: As a note, I wouldn't worry about the VFD fading under normal bench use unless you have a habit of always leaving all your instruments on. It's when it sits on a production line in use 24x7 for 10-20 years that you will notice fading. Sometimes people do this in labs, too, so it's important to check that the VFD is good when you receive it. The 34401A by default shows only 6 digits so that 7th digit is often brighter than the others.In general it's a nice instrument and the one I use the most, mainly because unlike the Keithley 2001 it has cap and diode tests, and unlike the 34465A comes on instantly when I want to check something like the capacitance of an unmarked SMD cap I find on the bench. The K2001 is vastly faster and the 34465A more accurate (especially for low current measurements, usually with the 34401A logging the burden or load voltage), but the 34401A is a nice instrument. Good footprint and form factor that will stack nicely with other instruments. Very clear and readable display (unlike incident LCDs). Nothing not to recommend about it if the price is right.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 05, 2015, 07:01:12 pm
content: Quote from: deadlylover on November 05, 2015, 01:46:54 amThanks for the heads up. I read the thread and posted my thoughts in that thread. The real test will be does it work correctly next week.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: November 05, 2015, 07:55:14 pm
content: Quote from: Scottjd on November 05, 2015, 07:01:12 pmNot really a test, the fakes seem to work just fine. To the point I don't think it is a huge deal that it is a fake.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 05, 2015, 08:20:24 pm
content: Quote from: PedroDaGr8 on November 05, 2015, 07:55:14 pmWell beside my opinion of people that make fakes. I guess the huge deal would be they sell them at a higher cost then what they are worth based on another companies name a reputation. That's a big deal, I could have gone for one that is $75 cheaper and might have worked just as good (with a warranty) with all of keysights software.I just found out you can register the device if you register on keysight. And guess what, my warranty was activated and expired already. I find it hard to believe keysight isn't already aware of this. But both customer service Agents I spoke with claim they never heard of this before.Now for my personal rant.Well, mine is registered and says the warranty expired. It should be showing one year for the date of registration. So the serial number was valid. This is now escalated to keysite fraud department and I should be getting a call next week. I have 30 days to return it, but since the serial was already registered I'm surprised they have not picked up on this until now. Looks like I'll be shutting down another Amazon store.Since I spent 16 years working digital security, fraud, shutdown down the biggest credit card fraud ring once at that time and securing networks by finding vulnerabilities to protect customer information. Well I don't view this fraud any different from credit card fraud or ID fraud. It's stealing the reputation of the other companies name, their ID.It's stealing from keysite. And the people that buy it may have it burn out to find out its fake past the return date, so it's steeling from them also. All this while the forger gets rich from other people's engineering and designs. Maybe the people selling them don't know? Or maybe they got lied to when they bought a block of them and also found out late.Either way it's a lie. It's taking money and jobs away from people, part of it may be the big companies fault for outsourcing manufacturing and they took the design that way? Or it may have been reversed engineered since some people are talented enough to do such acts. Nothing against that talent, I have to do the same with software code to see if it's secure. But it's my ethics that prevent me from making something malicious to steal from other people.I guess the point of this rant is..... I don't care if it works. I don't support or condone forgeries. Not a $130 GBIP to USB or a $20 set to tweezers. It doesn't matter the cost, it will go back if it works or not.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 05, 2015, 08:52:38 pm
content: Quote from: Scottjd on November 05, 2015, 08:20:24 pmAt the time I found out, that one of mine was a fake....1. I did not want to believe that someone would fake such a device and it took me a while to accept this fact2. I also contacted Keysight but it seemed they had no interest in this case, but I did not get connected to any fraud division3. I got rid of it4. I enjoy the real deal of genuine Agilent GPIB to USB adaptersThe problem here is, that you can not tell it is a fake, until you have dismantled the item.And definitely not, until you have it in your hands.The selling price should be a dead giveaway but then alsoi genuine Agilent parts sometimes sell for little money.It is really good, that you got the Keysight fraud division involved.I am happy to supply plenty of pictures I took, if needed.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 06, 2015, 05:21:52 am
content: Quote from: HighVoltage on November 05, 2015, 08:52:38 pmThanks, I may take you up on the picture offer. As I found out if you go to KeySight web site, register an account. Verify you email address. Then add the model and serial number to the items you own in your profile.When I did this it told me the warranty was up in 2011 because this serial number was already registered.So that would be a quick way of finding out its a fake and that the serial number has been used before without opening it up.I guess also with the right patients you can peal back the label just enough to get the screw out also and put the label back when done and still have it look like it wasn't opened. I think Dave did a video and did this once also.Thanks,Scott

author: macboy
author_rank: Super Contributor
timestamp: November 06, 2015, 04:08:56 pm
content: Quote from: Scottjd on November 05, 2015, 01:12:04 amThe "Agilent" font and logo on your box and the unit itself look far and away much more genuine than on mine. For some reason I still had the box from mine (bought 2-3 years ago), and inspecting it with newly distrusting eyes, it is clear that it is fake, especially the printing on the white label. The font is just wrong, some generic sans-serif font used for "Agilent". You just know that they would never print their name randomly like that. Yours, in contrast, looks "right". Night and Day. You may have the real deal there, and the low price you paid may just be reflecting the low price set by the flood of fakes on the market.

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 06, 2015, 07:39:31 pm
content: Quote from: macboy on November 06, 2015, 04:08:56 pmWell I guess that goes to show just how good the fakes have gotten.One thing that definitely pointed to this one I have being fake is the fact that the serial number was already registered with another keysight customer in 2010, so the warranty expired in 2011. But I just happened to make a on the fly video of me opening the box from start, so I have good proof that I'm not just trying to rip off keysight.It's by pure luck I decided to do the video, since I don't normal do videos of opening item, or unboxing videos.But it shows I received this new and sealed. Not that I bought I used item and I'm trying to scam keysight to replace it under a warranty that expired.The video will also show keysight that their is a problem and these are being replicated with valid serial numbers from their system. So someone had to get this list of valid serial numbers and sell them, or this is a current employee that made the fake designs and is selling them.When I say current employee that may not mean they get laid by keysight, it could also be an employee of the manufacturing plant. And the plant may be contracted by keysight, either way it's a leak of their information.Since so many of these seem to have flooded the sales and looks like their selling good at this price. Who knows if this person or team of people will start making some other more expensive fakes next that sell for thousands.My personals thought is that keysight should think about dropping the price on this item now since the price hasn't changed since they made it. This item is being phased out when you think of all the newer meters they make that have USB built in.,they could drop it to $99 and people would be sire to hopefully buy authentic. Or the fakes will go even lower???

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 14, 2015, 08:24:01 pm
content: And it finally arrived. I'm very happy with it, self test past. Measurements I tested passed.Looks in great condition for the age. Firmware is from 04-01-01, so it's probably at least 11 years old.I did a quick video when I received it a few days ago, but didn't get a chance to upload it unit today.Sorry for the shaky video, I do get the tripod part way in. My lab is under construction as I'm adding new audio and mic equipment to sound better and more constant on future videos.To bad I can't do a tear down or I'll voice the re-calibration next year, so it might be a year before I can see the date codes on the chips to confirm how old it really is.. But the reading before the calibration was done was impressive.http://youtu.be/FBYAJP8XVlw

author: deadlylover
author_rank: Frequent Contributor
timestamp: November 14, 2015, 09:12:30 pm
content: Nice to see your baby has arrived. ^^Hmm one of my 34401A is serial 3146A714xx and was made at around 1996ish, so yours is probably even older than mine by a little bit. My firmware was 07-05-02 IIRC.Was the cal data shown in the video all that they gave you? Or is your current cal certificate on the way to you in the mail?For the one shown in the video, I think they didn't even engage 6.5digit mode, it's almost useless. (bit of an exaggeration, but still, you paid for it so you expect to get your money's worth!)

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 14, 2015, 09:19:57 pm
content: Quote from: deadlylover on November 14, 2015, 09:12:30 pmI do have the NIST certificate and calibration data that was part of the price. The extra I paid for was the data I showed.These were the readings before he calibrated it. Showing were it stood before the calibration and knowing the last time calibrated gave me an idea of the drifting. But after looking at that, it doesn't look like this things drifts that much anymore.And thats exactly what I was looking for.Yea, I really want to open it up and find the date, oh well. Next year.....Maybe I can pull some more detailed information on the GBIP once I set it up. According to the manual it only displays 12 digits, but may have other notes and lines in the data that can only be seen over the GBIP interface.

author: deadlylover
author_rank: Frequent Contributor
timestamp: November 14, 2015, 09:30:03 pm
content: Quote from: Scottjd on November 14, 2015, 09:19:57 pmIf it's not too much trouble, could you please take a quick picture or two of the current cal certificate? I just want to see what the quality is like, in case I might order from their eBay store in the future. Make sure to block any names/address from the certificate.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: November 15, 2015, 12:00:39 am
content: For those in the USA, Global Test Equipment is doing a $75 special for Cal+Adj with Data (plus they pay for UPS ground shipping back to you). Just a heads up. Their special includes the 34401A, Keithley 2000 and some others plus a few counters.I posted more details about it here:https://www.eevblog.com/forum/buysellwanted/$75-calibration-with-adjust-and-data-for-a-variety-of-multimeterscountersetc/

author: Scottjd
author_rank: Frequent Contributor
timestamp: November 26, 2015, 10:32:38 am
content: Quote from: deadlylover on November 14, 2015, 09:30:03 pmSorry, I had forgotten to do this for you. Here is the picture of the cal cert.

author: fabioadriano
author_rank: Contributor
timestamp: June 07, 2016, 07:52:40 pm
content: Hi dears, i found this thread when i'm searching info about GREAT HP3457A ...& so i found a competition between two GREAT instruments(a) HP3457A&(b) HP34401AI have them both at home & i use them at work (here :http://www.inrim.it/gen/index.shtml#url1)... I think that THERE IS NO COMPETITION between (a) & (b) .... BUT if the rule is 'only one' , not even think about one minute my choice is: HP3457A !!!!surely HP34401A is 'smaller'is newerand is 'easier to use'but ... HP3457A is more accurate .. nothing else !!!p.s. i don't like competition ...this is ONLY my preference & use at work !!! (i.e. IF i MUST measure OUT of the laboratory sometimes i use also (b) )

author: Scottjd
author_rank: Frequent Contributor
timestamp: June 08, 2016, 12:05:22 am
content: Thanks for your thought. I didn't know the poll was still open and forgot to set and expiration date, so it's closed now since I have already bought one. Price was some of the factor, but size also made part of the decision for a home hobbiest. The bench is running out of room, especially after getting the microscope.It was more asking for opinions from people that have used both, not a competition. They are both great units. I just couldn't pass up a deal for the 34401A I made with a seller that added the bumpers, dropped the price a bit to match another post, included calibration before shipped to me, and another calibration a year after as long as I pay shipping to them. This way I can compare the cal data and see if it still drifting at all over a year of me using it. In fact the calibration done before mine when it shipped was in 2012 and it was still in spec. I was looking for an older one that hopefully stopped drifting. Being a home hobby I don't want to pay for a calibration every year, and it looks like I found one. But I will know for sure in 6 months when I send it back out to the same service center. And the GBIP works great once I found a USB adapter and is more enough for my needs. The only thing I've noticed is the rear and front ports are off a little with added resistance to the rear. But this switch is a common issue and not a big concern for me since I don't use the rear ports.I just ordered the Rigol DP820, I like the fact I will be able to calibrate this myself with some script people have wrote and the 34401A. So now using this meter I don't have to worry so much about having to pay for calibration on other items I buy as long as I know calibration procedures are available or a script to make it go faster. The last thing on the list is a arbitrary function/signal generator. But I have time to figure that out for what I mainly tinker and work on.ScottQuote from: fabioadriano on June 07, 2016, 07:52:40 pm