Budget 10V (etc.) Voltage References/Standards on the marketplaces out there

[Rax]

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.

[bdunham7]

https://voltagestandard.com/001%25-10v-reference

I 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. 

[guenthert]

   I got one of fredchu's (seller's name on eBay) LT1021 based 10V references [1] (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).
 
[1] 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

[ScoobyDoo]

You can read more about adventures of "Awesome14 (Kaysert - Tom Kayser)" here:

Calibratory D-105 DC Precision Voltage Reference Standard
https://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 careful

Best regards
ScoobyDoo


kaysert
https://www.grelly.com/itm/10-volt-10-v-dc-prec-voltage-reference-standard-nulled-to-fluke-732a-or-732b-251756273626

We know from past that Kaysert = Tom Kayser = Awesome14

[RoadDog]

You can read more about adventures of "Awesome14 (Kaysert - Tom Kayser)" here:

Calibratory D-105 DC Precision Voltage Reference Standard
https://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 careful

Best regards
ScoobyDoo

Oh 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 😂

[iMo]

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.

[J-R]

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.

[Rax]

You can read more about adventures of "Awesome14 (Kaysert - Tom Kayser)" here:

Calibratory D-105 DC Precision Voltage Reference Standard
https://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 careful

Best regards
ScoobyDoo

What 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?.... 

[HighVoltage]

What 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?.... 

Believe 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.

 

[RoadDog]

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 🤣

[Gyro]

I think I remember him describing that matrix board as 'low hysteresis pcb'. It's in the thread somewhere.

[HighVoltage]

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 587LQ
https://www.eevblog.com/forum/metrology/geller-labs-svr-lars-walenius-black-edition-with-587lq/

[RoadDog]

And the copper foil was a special "passive heat pipe technology" that came from god.
Good old days.

Too 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.

[RoadDog]

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?

[iMo]

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..

[Andreas]

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 regards

Andreas

[jonpaul]

Reading this, I looked at the sit e

https://voltagestandard.com/001%25-10v-reference

Sent a few questions via email re availability and connectors etc,
 and potential order to Doug at
 voltagestandard.com

But no reply.

Wonder if he is still in business and responds to that address.

Many thanks

Jon

[iMo]

Reading this, I looked at the sit e
https://voltagestandard.com/001%25-10v-reference

Be careful with the epoxy LT1021-10 references. That is a great 4 digits reference, imho..

[mikerj]

You can read more about adventures of "Awesome14 (Kaysert - Tom Kayser)" here:

Fantastic, that was well worth the 45 minutes I spent reading it

[ScoobyDoo]

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 regards
ScoobyDoo

[Alex Nikitin]

It looks like the majority of these units use gold plated but brass body binding posts.

Cheers

Alex

[J-R]

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: 10.000,00V
Calibrated 34461A - PDVS2mini: 9.999,955V ; 10V: 9.999,955V (average)
Keithley 2010 - PDVS2mini: 10.000,011V ; 10V: 10.000,014V

To 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).

[Gyro]

It looks like the majority of these units use gold plated but brass body binding posts.

Cheers

Alex

Yes, 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.

[metasequoia]

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

[mawyatt]

We just received our 10 Volt Reference from Doug Malone the sole owner of voltagestandard.com

Very well packaged, quick shipping, and the VREF-10 is looks very nice 

We'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,