Budget 10V (etc.) Voltage References/Standards on the marketplaces out there - Page 1
Forum section: electronics / general

author: Rax
author_rank: Super Contributor
timestamp: January 25, 2023, 03:02:02 pm
content: Hi all,I wonder if anyone has tried, and has some measurements, results, thoughts on some of these voltage standards on the various marketplaces out there. They seem to go for somewhere between $140 - $210 (USD), and most are adjusted against your typical 3458A, maybe nulled against a Fluke standard, etc.Is there any one that is particularly good?Some are 2W, others 4W, and there are other functionality and features differences.Some of the sellers are zildjianboy7, kaysert, etc.

author: bdunham7
author_rank: Super Contributor
timestamp: January 25, 2023, 04:07:05 pm
content: https://voltagestandard.com/001%25-10v-referenceI have one of Doug's earlier versions, back when he only guaranteed 24ppm, had an open-chassis w/ solder turrets for terminals and was just starting to add the extra diode temperature compensation. It has been excellent, very stable and a better temp coefficient by far than my Fluke 731. I can highly recommend the voltagestandard.com for both product and service. This latest model looks even better than before--although the price has gone up a bit, I think it is pretty cheap for what it is and what is included now. They also actually send their 3458A to Keysight's primary standards lab for calibration--some of the competitors are using more questionable references. That may not seem to matter much in the 10-ppm class, but mine has been way better than advertised.

author: guenthert
author_rank: Frequent Contributor
timestamp: January 25, 2023, 06:15:56 pm
content: I got one of fredchu's (seller's name on eBay) LT1021 based 10V references  (meanwhile he also offers LM399 based ones) almost a year ago. Works like a charm afaict. Unfortunately a good chunk of my gear is still in storage, so I can't sensibly characterize it.I like that it has screw/banana-plug combination terminals. They are gold color (gold flashed?), not sure if they are truly low thermal EMF terminals though (there is no claim that they would be). Oddly, the same kind is used for input and output (clearly marked though, albeit with sticky labels -- it's not meant to be used in decades like old -hp- gear).I also like that he publishes pictures of the internal construction. Removes the mystery and temptation to open one up oneself (and potentially invalidating calibration).EDIT: with the recent addition of a 50+ y/o -hp- 735A DCV transfer standard, I'm now in a better position to evaluate the LT1021 based 10V voltage reference (fortunately I already had a DV211 "dekavider" KVD). Still can't say much about long-term stability, but at least the short term stability / [absence of] noise was good enough to verify the power-on behavior (limit of hysteresis) of the -hp- 735A (see attached, the green line being the differential voltage between those sources).https://www.ebay.com/itm/133639951608?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D245488%26meid%3D740e89ab81a9416ea9d79e5598cc60b2%26pid%3D101195%26rk%3D2%26rkt%3D12%26sd%3D134257761418%26itm%3D133639951608%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv11WebTrimmedV3MskuWithRevOptLambda85KnnRecallV1WithCassiniImageSim%26brand%3DUnbranded&_trksid=p2047675.c101195.m1851&amdata=cksum%3A133639951608740e89ab81a9416ea9d79e5598cc60b2%7Cenc%3AAQAHAAABMBTnULwZvkwwvWb54Sp3TESux6kFTXxeByyFeTbBEJTAHELVvJ%252BnpiRCZsaEJO6SgqSsQIHvbg9YL2jxELBYJZWPAuIRQj6%252FC29lmsqlxuBAp5GZml%252B6FjHNFCmsArHfMC4jQ3nozzbfp%252BfjnKt%252FtKzCUl3FiGFoFWL2nZyg4EmAmpHfYbAOSWUQ9qzNLM8oaLQ8yWPqw97HEa%252FdNBNVmdQuwcxRJ9lwFup6fJ9Y4BPJa1kejiwmYKyv0fAT5MjN1e0IZVJALwW9dsRwfB02OlEzva9%252BQCzLKi0YUJIf3oOU9KTyFSbgw2WZHqIJUbhf%252BvfZlgQYlFV86ktKC5yLpJ4wVlVe45z0%252FApZMOFJH5wPJYQEShj9MZ4CSNtN6LSauespCDm%252FBxetQUasnyYKYIo%253D%7Campid%3APL_CLK%7Cclp%3A2047675

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: January 25, 2023, 06:49:58 pm
content: You can read more about adventures of "Awesome14 (Kaysert - Tom Kayser)" here:Calibratory D-105 DC Precision Voltage Reference Standardhttps://www.eevblog.com/forum/metrology/calibratory-d-105-dc-precision-voltage-reference-standard/Search for the teardown EEVBLOG members have done on Awesome14 artwork - be carefulBest regardsScoobyDookayserthttps://www.grelly.com/itm/10-volt-10-v-dc-prec-voltage-reference-standard-nulled-to-fluke-732a-or-732b-251756273626We know from past that Kaysert = Tom Kayser = Awesome14

author: RoadDog
author_rank: Regular Contributor
timestamp: January 25, 2023, 07:38:18 pm
content: Quote from: ScoobyDoo on January 25, 2023, 06:49:58 pmOh man that thread is gold. I had to force myself to stop reading because I have to get back to work but what a piece of work that guy is. I can’t wait to read more of his replies this evening 😂

author: iMo
author_rank: Super Contributor
timestamp: January 26, 2023, 06:52:13 am
content: You have to see the pcb with parts on it and you'll get immediately the point - whether the reference is worth the $$, or it is just a BS.

author: J-R
author_rank: Super Contributor
timestamp: January 26, 2023, 08:29:35 am
content: I have the earlier 0.003% 10V reference and two 0.01% references from voltagestandard.com as well as the DMM Check Plus w/LC board. I highly recommend both companies and they are great products for the price, but all those fixed voltage references sat on the shelf once I got Ian's PDVS2mini.I do think the DMM Check Plus is a must-have for a budget starter-set of standards.

author: Rax
author_rank: Super Contributor
timestamp: January 27, 2023, 02:30:10 am
content: Quote from: ScoobyDoo on January 25, 2023, 06:49:58 pmWhat have I ever done to you?... I had a perfectly good couple of hours this afternoon, and you've tricked me, and sucked me into this juicy, evil and... splendidly insane thread. How do I get my hours back?....

author: HighVoltage
author_rank: Super Contributor
timestamp: January 27, 2023, 10:05:39 am
content: Quote from: Rax on January 27, 2023, 02:30:10 amBelieve me, you do not want your hours back.This is the funniest metrology thread ever and you will never forget about it.I remember the day, when I first got this reference and opened it up.My facial expression must have been priceless.So that we never forget, in honor of Awesome14, here are my pictures again from those days.

author: RoadDog
author_rank: Regular Contributor
timestamp: January 27, 2023, 11:58:23 am
content: Yeah certainly the funniest thread I’ve come across here. I’m only up to about page 25 so far. Been entertaining.It’s interesting how he starts to come around a little although still pretty sensitive and wacky at times.He’s still there plugging away on eBay. Looks like he has sold about 440 of his references between the cheaper and more expensive one. His description mentions a low hysteresis pcb design now. It also includes a strange diatribe against the LTZ1000 🤣

author: Gyro
author_rank: Super Contributor
timestamp: January 27, 2023, 12:20:48 pm
content: I think I remember him describing that matrix board as 'low hysteresis pcb'. It's in the thread somewhere.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 27, 2023, 03:26:02 pm
content: And the copper foil was a special "passive heat pipe technology" that came from god.Good old days.But more seriously:The Geller Labs voltage reference was one of the first one around.Lars Walenius (RIP) had developed the temperature control for this board.We started a thread a few years ago:Geller Labs SVR, Lars Walenius black edition with 587LQhttps://www.eevblog.com/forum/metrology/geller-labs-svr-lars-walenius-black-edition-with-587lq/

author: RoadDog
author_rank: Regular Contributor
timestamp: January 27, 2023, 04:40:51 pm
content: Quote from: HighVoltage on January 27, 2023, 03:26:02 pmToo bad the Lord didn’t pass on some divine soldering skills.I’m currently working on my first pcb design in Kicad for some LM399’s. Bit of a learning curve so I could understand why he started off just using prototype boards. You’d think he’d have a printed board in there to save time by now. Someone even offered to design him one for free.

author: RoadDog
author_rank: Regular Contributor
timestamp: January 27, 2023, 04:48:53 pm
content: I have looked at Doug’s and will likely pick one up once I’m ready to build my 399 based references so between that and my 34401 I can get a good idea where they’re at.I was thinking building a burn in board for the 399’s with sockets. Not sure how to power multiple references at once though. Ian posted a pic of a 10 channel board that looked interesting but no schematics.Any tips for powering multiple 399’s in sockets for burn in?

author: iMo
author_rank: Super Contributor
timestamp: January 27, 2023, 04:57:18 pm
content: Put all heaters in parallel to say Vcc=15V DC, and each cathode via a resistor to the 15V such it flows say 1.2mA through it (6k8 in this case). Put a diode in series with the power for safety reason, and block the Vcc against the GND with 100uF/25V capacitor in parallel with 100nF ceramic. That is all. Let it burn-in for 2-3months. You may put a LED there via a resistor (ie 10k) as well, such you can see it still runs..PS: you may use a higher Vcc voltage, like 19V DC from a notebook power adapter, do use 10k resistors with 19V. Mind the polarity..

author: Andreas
author_rank: Super Contributor
timestamp: January 27, 2023, 06:51:34 pm
content: Hello,but do not forget to "Kelvin Sense" each individual zener.If you want to measure during "burn in".There may be several 100 uV along the heater ground line.with best regardsAndreas

author: jonpaul
author_rank: Super Contributor
timestamp: January 29, 2023, 10:14:33 am
content: Reading this, I looked at the sit ehttps://voltagestandard.com/001%25-10v-referenceSent a few questions via email re availability and connectors etc,and potential order to Doug atvoltagestandard.comBut no reply.Wonder if he is still in business and responds to that address.Many thanksJon

author: iMo
author_rank: Super Contributor
timestamp: January 29, 2023, 10:33:20 am
content: Quote from: jonpaul on January 29, 2023, 10:14:33 amBe careful with the epoxy LT1021-10 references. That is a great 4 digits reference, imho..

author: mikerj
author_rank: Super Contributor
timestamp: January 29, 2023, 12:03:39 pm
content: Quote from: ScoobyDoo on January 25, 2023, 06:49:58 pmFantastic, that was well worth the 45 minutes I spent reading it

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: January 29, 2023, 01:03:05 pm
content: Hello -This Harwell (NYC - USA) 10V DC reference might be also a good solution:https://www.ebay.com/itm/204178697194?hash=item2f89ffabea:g:NzQAAOSwIzxiDH0-Best regardsScoobyDoo

author: Alex Nikitin
author_rank: Super Contributor
timestamp: January 29, 2023, 04:02:51 pm
content: It looks like the majority of these units use gold plated but brass body binding posts.CheersAlex

author: J-R
author_rank: Super Contributor
timestamp: January 30, 2023, 11:29:07 am
content: It really should be stated what all these references are planned to be used for, and whether that use case is reasonable.The OP mentioned a budget reference, so I don't think they are planning to use it to calibrate 6.5, 7.5 and 8.5 digit DMMs (even if you could). But they could probably be used to sanity check up to 7.5 digits especially if you have more than one reference and have them regularly calibrated.I do use the fixed voltage references to verify the PDVS2mini on occasion. Today I compared the PDVS2mini to the voltagestandard.com 0.003% 10V reference. The PDVS2mini is almost 3 years old (never calibrated) and the 10V reference was calibrated about 7 months ago (it's about 2 years old). Both came with calibration data stating 10.000,000V and still read identical at least with the equipment I have available:Calibrated 34401A - PDVS2mini: 10.000,00V ; 10V: 10.000,00VCalibrated 34461A - PDVS2mini: 9.999,955V ; 10V: 9.999,955V (average)Keithley 2010 - PDVS2mini: 10.000,011V ; 10V: 10.000,014VTo get these readings, I had everything on for most of the day (6 hours or so) and the room was ~71F throughout. Not die-hard volt-nuttery, but some precautions were taken...Based on my records, the references from voltagstandard.com and DMMCheck Plus do drift a bit early on, which is to be expected and they both include free calibrations for two years (you have to pay shipping).

author: Gyro
author_rank: Super Contributor
timestamp: January 30, 2023, 02:27:45 pm
content: Quote from: Alex Nikitin on January 29, 2023, 04:02:51 pmYes, they're (like the ones on Dave's uCurrent) ordinary Gold plated speaker terminals. Luckily thermocouple effects (normally) aren't that important at the 10V level and specified degree of accuracy.

author: metasequoia
author_rank: Newbie
timestamp: January 30, 2023, 03:49:51 pm
content: Hello; I am Doug Malone the sole owner of voltagestandard.com, sell on eBay as "zildjianboy7", and would like to correct the above comment that I and/or my products are some how related to Kaysert- nothing could be further from the truth. I, alone, am responsible for the design, fabrication, and calibration of the voltage references that I sell and they are not associated in any way with Kaysert/Awesome14.Thanks,Doug

author: mawyatt
author_rank: Super Contributor
timestamp: January 31, 2023, 01:51:36 am
content: We just received our 10 Volt Reference from Doug Malone the sole owner of voltagestandard.comVery well packaged, quick shipping, and the VREF-10 is looks very niceWe'll let the reference get acclimated to it's new home here in Florida with higher temperature and humidity before making any serious measurements and comparisons.Doug was even kind enough to do the cal at 76F since we are usually warmer than the usual lower cal temperature!Best,

author: guenthert
author_rank: Frequent Contributor
timestamp: February 21, 2023, 11:48:08 pm
content: Quote from: Gyro on January 30, 2023, 02:27:45 pmIn case of fredchu's LT1021 reference it's worse though: plate and bottom of the nut are plastic; a wire must be threaded through the hole in the post to make more-or-less contact. It's one of those 'what were they thinking' things.

author: Rax
author_rank: Super Contributor
timestamp: February 22, 2023, 12:35:26 am
content: Quote from: J-R on January 26, 2023, 08:29:35 amI missed this part at the first go around. I can't find much info on this - is this available? I see a review, but not much else beyond that, but still looking into it.

author: Andreas
author_rank: Super Contributor
timestamp: February 22, 2023, 05:04:11 am
content: https://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-2-mini-detail

author: Rax
author_rank: Super Contributor
timestamp: March 09, 2023, 02:10:36 am
content: Quote from: guenthert on January 25, 2023, 06:15:56 pmguenthert - you seemed quite a bit more critical in your later post; have you reconsidered your initial take? I was just going back to reviewing these suggestions and fredchu's LM399 reference has just come into my radar...

author: guenthert
author_rank: Frequent Contributor
timestamp: March 09, 2023, 05:22:35 pm
content: Quote from: Rax on March 09, 2023, 02:10:36 amNot really. The LT1021 based reference performs as claimed as far as I can tell. I just wished better posts (on the output) would be used, but those would be driving up the cost. That probably doesn't make any sense on a LT1021 based reference, but something to be considered for a LTZ1000 based one, perhaps also for a LM399 based one.

author: Rax
author_rank: Super Contributor
timestamp: March 11, 2023, 02:25:14 am
content: It seems that I may be heading into getting a 731B and a 510A (1kHz)...A lot of members of this community seem to use these 731s for secondary (quasi-primary?....) bench references (I know they're not in the same league as the 732s!...). The 510A seems more like a bonus from that one transaction I am in the middle of.When I'll recover (a few coins accruing in the hobby chest), I'm thinking I may get one of those fredchu's LM399 based references. I'm still not 100% sure I understand how one (731) stacks against the other (fredchu LM399).

author: J-R
author_rank: Super Contributor
timestamp: March 11, 2023, 09:38:30 am
content: Of the vintage Fluke stuff, perhaps also check out the 515A. It has a fair amount of flexibility, relatively speaking. Having one adjusted and calibrated may not make a ton of sense due to the excessive amount of manual tweaking involved, so maybe combine it with a good, calibrated 6.5 digit or better DMM instead.

author: branadic
author_rank: Super Contributor
timestamp: March 11, 2023, 03:06:10 pm
content: Multiple options are available, depending on how much gold you want to spend:Guildline 4410https://www.ebay.com/itm/295245155830Harwell VR-5https://www.ebay.com/itm/204178697194If you buy one or more of the Harwell please provide some teardown images to the community.-branadic-

author: Rax
author_rank: Super Contributor
timestamp: March 11, 2023, 03:17:30 pm
content: Quote from: J-R on March 11, 2023, 09:38:30 amI would do the former anyhow (currently neck deep into an 8505A including all hardware and software calibration adjustments, in addition to full repair - the motherboard needed being replaced and other smaller issues) and already have the latter (freshly calibrated/adjusted/stickered 8502A).Once the 8505A is fully working and adjusted (almost there), I'll then of course add 7.5 digit capabilities on my bench. Happy camper.

author: MegaVolt
author_rank: Frequent Contributor
timestamp: March 21, 2023, 12:25:04 pm
content: https://www.ebay.com/itm/334432987035

author: RoadDog
author_rank: Regular Contributor
timestamp: March 22, 2023, 12:05:41 am
content: $43 reference off eBay.Reclaimed LM399 and LT1001. Claims all the other parts are new.I figure I’ll watch it with my 34401. I imagine this should drift more than my aged meter although I’m not sure how much.I’ll measure its load sensitivity and PSRR. Maybe mess with some capacitive loads and see what it does. Not sure of what kind of setup to do for measuring TC although I’d like to figure out a setup for that. Kind of new to this. Any tips for that or other things I should try to measure? Anything else to poke and prod at?

author: Andreas
author_rank: Super Contributor
timestamp: March 22, 2023, 08:22:00 pm
content: My standard program for measurements would be:- T.C. within 25+/-15 deg C environment (perhaps a heater box in a car cooling box, or a proper refrigerator)- Ratio T.C. between 7V and 10V output- PSRR- 1/f noise (0.1 .. 10 Hz Amplifier 10000 fold) with screening for popcorn noise- optional wideband noise (10Hz-100kHz with AN83 amplifier)- for LM399: sensitivity to tilting.- unheated vs. heatet output voltage- ageing drift- optional EMI drift over 100kHz - 60 MHzsee also here: overview picturehttps://www.eevblog.com/forum/metrology/adr1399-reference/msg4737989/#msg4737989with best regardsAndreas

author: deepfryed
author_rank: Unknown
timestamp: October 02, 2023, 12:22:07 pm
content: Quote from: Rax on January 27, 2023, 02:30:10 amOh dear, I stumbled upon this and my whole evening's been used up reading the thread which I haven't finished. I hope the poor fella got some help. He still seems to be selling it, though the price is over $1000aud now