Are cheap AD584 units worth it?

[Muttley Snickers]

I cant help you with the manufacture date but others will know, my question is were either unit supplied with reference figures and can they be counted upon, the AD584LH I received was not supplied with figures and I have been corresponding with the Ebay seller who was most apologetic and openly offered a full refund even though I did not ask for nor seek one.

This is no big deal really but for anyone else counting on those values being both supplied and accurate it might be of importance and as mentioned most people are sick to death of stuff that takes weeks to arrive only to turn up faulty or not as described, not all of us seek the bottom dollar just a fair and reasonable deal.

[Mark Hennessy]

The other one is the AD584L it looks brand new, the markings are lasered (you can see the individual dots under a microscope) and has a datecode 1015 so week 15 2010.
The big question is, did AD make these still in 2010 and were they indeed lasered or is the last one a fake chip? Anyone that can give a decisive answer on this one?

I don't know, but am watching this closely. An awful lot of these are exactly like your picture, including one of mine.

My one appears to meet the L spec, so if they are fakes, they're good 

[RobK_NL]

The datasheet Rev.C was issued in 2012 and one of the differences with Rev.B is that the "L" was deleted. So it could well be that it was still made in 2010.

[Kjelt]

my question is were either unit supplied with reference figures and can they be counted upon

The K version in the plexibox had a sticker with reference voltages which I could verify upto the first 4 digits after the , so pretty good AFAICT.
The L version had the already much mentioned standard leaflet with numbers that do not correspond to the unit so no good.

[guy48065]

I bought 2 of the L-version boards and am pleased with the performance.  Well within AD specs.  These have to be legit, IMO.

#1: 10.0V = 10.00274  7.5V = 7.49969  5.0V = 5.00269  2.5V = 2.49918
#2: 10.0V = 10.00158  7.5V = 7.49881  5.0V = 5.00162  2.5V = 2.49829

2ppm/V increase @ 10V with an increase in supply from 15.0 to 20V.
28ppm/mA decrease @ 10V with resistive load (tested with 10K, 5K & 2K).

All measurements taken with an in-cal 34401A (10V = 9.99999 on cert.), 6-digit Slow mode, after minimum 1 hour warm-up of everything.  I bagged the board and wrapped it in a couple shop towels to isolate it from HVAC and equipment fans.  I'm particularly impressed with the lack of drift over time for a $6.59 "plug & play" module!

Mine came with the same "bogus" cal sheetlet.  Does anyone here read chinese?  Maybe it states the figures are "typical" and not Actual. 

[Kjelt]

So here are my measurements, however not as official as guy48065 has done with one hour warmin etc. just power up two Keithley 2000 not calibrated for at least 8 years but that's all I have here 
The K-unit figures are pretty spot on, the L-unit figures are fiction.

[escape]

Sorry to revive an old thread, but it made more sense to me to just keep it in here.

Regarding the date codes, the code on the KKMOON board I bought from a seller on Amazon last month is 9107.  Is it possible it's this old?

BTW, it did come with hand printed values.  I don't have a way to verify these values though.

Mine came with a micro-USB charging port instead of the round port found on older models.

[Kjelt]

Regarding the date codes, the code on the KKMOON board I bought from a seller on Amazon last month is 9107.  Is it possible it's this old?

Yes those are recycled from old electronic garbage, the only way why they are real and this cheap.

[MacMeter]

Sorry to revive an old thread, but it made more sense to me to just keep it in here.

Regarding the date codes, the code on the KKMOON board I bought from a seller on Amazon last month is 9107.  Is it possible it's this old?

BTW, it did come with hand printed values.  I don't have a way to verify these values though.

Mine came with a micro-USB charging port instead of the round port found on older models.

Can you link the EBay page you bought yours on? Thanks!

[innkeeper]

kinda makes you wonder if the 2015 date is the calibration date of the agelint used and not the date they did the voltage check.

[escape]

Can you link the EBay page you bought yours on? Thanks!

Sorry for the late response.  I bought mine on Amazon, because I didn't feel like waiting for it to be shipped from China.

http://a.co/45CANQr

But it was cheaper back when I ordered it.

[Muxr]

If you have a decent power supply handy I would save a few bucks and skip the KKmoon unit. KKmoon unit is built well and it's fairly convenient, however the boost converter does add noise.

I did a full day run with both the KKmoon AD584 and the one sold by Alice. Also worth noting KKmoon's battery lasts about a day and a half of full operation, before it needs to be recharged.

If you're just looking to check your 4.5 digit meter, you're probably fine either way though.

[metrologist]

Super Dooper! I bought mine the other day from t-happy on ebay, same seller as mojoe's units.

I have no way to check it, unless I get someone to do it for me...

[mokeman3]

I recently bought a number of these, and have written about them (including schematics and measurements) here: http://www.markhennessy.co.uk/ad584_references/ 

Thanks! I ordered the KKMoon (#1) today and another cheaper one (#2) with the better L version, going to swap them and keep the kkmoon with a l version, lets see what we get.

I got my KKmoon (#1) from tomtop_sales today too, but after learning about the (#2) with the better L version, I just bought one of those ones with the 15-volt battery cut out in the PCB, and thought about doing the same thing: putting the better L version device in the pelexi-case KKmoon box.

Q: did you do that with yours ?

The AD584 that is in my KKmoon, looks really beat up, and it doesn't have the official Analogue Devices "triangle" on it, and I can't make out the date code. Makes me wonder if it's a AD knock-off, and not the real thing.

But I don't know that China (or any other place) has the ability to make devices like this anyhow, do they ?

And it does seem to drift like a mo-fo. It seems to get in a mode where the output isn't right, and you have to turn it off, and back on again.

Mine has a micro USB, but the charging LED is orange, not blue. The battery is also quite a bit smaller than earlier unit's I've seen.

Question for you folks with in-cal Agilent 34401A's and the like: have you thought about offering a service to members here to check these things for us, and offering an "actual reading" slip (or sticker) ?  Might be a way to turn a fast buck, and help out some of the folks with less accurate meters.

[Muxr]

The AD584 that is in my KKmoon, looks really beat up, and it doesn't have the official Analogue Devices "triangle" on it, and I can't make out the date code. Makes me wonder if it's a AD knock-off, and not the real thing.

I have both versions of the KKmoon reference. The one with the logo and the one without. I have not found them to be different in TempCo and noise (haven't had them long enough to ascertain drift).

Question for you folks with in-cal Agilent 34401A's and the like: have you thought about offering a service to members here to check these things for us, and offering an "actual reading" slip (or sticker) ?  Might be a way to turn a fast buck, and help out some of the folks with less accurate meters.

You have multiple options here. We are currently trying a traveling reference concept in the https://www.eevblog.com/forum/metrology/usa-calibration-club/msg1209295/#msg1209295 USA callibration club. Once the reference makes the full trip, we can compare the readings (some folks have in-cal instruments). This will take awhile.

Your other option is ordering a reference from voltagestandard.com:

As a benefit to our customers, and to keep the cost of ownership as low as possible, recalibration is free for the first two years after purchase- just send it back to us and for USPS Priority return shipping please include $7.00 in stamps or US currency or PayPal payment to doug@voltagestandard.com.  After two years the calibration charge is $10.00 plus shipping.

http://www.voltagestandard.com/-.html

[mokeman3]

Well I started reading the cal club thread with the Traveling Reference Concept, and didn't get all the way thru it, but I've sorta lost sight of the goal of it.

And I have been in touch with Doug at voltagestandard.com.  What I was really after was his "DMMCheck" product, but he disco'd it. I really wanted one, and was after the current, and resistance standard that he offered.

But I fell prey to this guy's video starting at minute marker 20:00, and his findings:

But I should have just gotten the 'pentaref' instead of the KKmoon, - and I may still do that.
The guy isn't even that far from me, - he's in the State of Washington too, about 1.5 hours South of here.

Oh well, live and learn.

As far as the KKmoon, the output seems to be "porpoising" some (at least on the 5-volt range), and I can see the segments on the end of the bar graph on the Fluke 89 IV flashing back and forth, and that doesn't seem right (nor that noise).

I think I'm going to dig into it to isolate the switching power supply, and just power the can directly with ~15 (proly 18) volts of pure (battery) DC to see if any of that goes away.

[alm]

Your other option is ordering a reference from voltagestandard.com:
[...]

Unfortunately Doug no longer ships his products outside the US:

Please note that we no longer ship to international destinations- only orders that are shipped to addresses within the USA are accepted.

So as far as affordable readily available voltage standards with something resembling calibration, the AD584 units appear to be the only game in town now for people living outside the US. Except for our +/- 2 ppm with shoddy soldering on a protoboard friend .

[Muxr]

Your other option is ordering a reference from voltagestandard.com:
[...]

Unfortunately Doug no longer ships his products outside the US:

Please note that we no longer ship to international destinations- only orders that are shipped to addresses within the USA are accepted.

So as far as affordable readily available voltage standards with something resembling calibration, the AD584 units appear to be the only game in town now for people living outside the US. Except for our +/- 2 ppm with shoddy soldering on a protoboard friend .

Didn't realize about shipment outside of US. Bummer.

There is also this AD588 board.. http://www.ebay.com/itm/111840217453?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It appears to have better tempco than the best AD584 reference I have.

I am getting a bit of popcorn noise with it, but it's not bad at all, there is also less noise. The only thing is, it requires both a +17V and a -17V +15V and a -15V rail.

[alm]

Thanks for posting those measurements! At least your 588 sample looks quite a bit better than your 584. Of course both share the issue of the somewhat dubious calibration (slip of paper/sticker).

[Muxr]

Thanks for posting those measurements! At least your 588 sample looks quite a bit better than your 584. Of course both share the issue of the somewhat dubious calibration (slip of paper/sticker).

No problem. I think you're right. For cross checking handheld DMMs I think it's fine, but I would take the "calibration slip" with a grain of salt. I don't have enough confidence in my lab to determine how much they are off by yet, but even just the 24 hour and TempCo drifts don't seem suitable for anything that has above 5 1/2 digits worth of resolution.

[mokeman3]

Which leads back to a comment I made earlier: Who here would be willing to spot-check some of these KKmoon devices with an in-call 5-1/2+ digit meter and supply a new slip of paper ?

That's something that I would be willing to compensate someone for.

[Muxr]

Which leads back to a comment I made earlier: Who here would be willing to spot-check some of these KKmoon devices with an in-call 5-1/2+ digit meter and supply a new slip of paper ?

That's something that I would be willing to compensate someone for.

None of my instruments are recently calibrated (Keithley 2015, Fluke 8045A and 8046A as well as my HP 3458A). However I am getting a new 0.003% reference from Doug (VoltageStandard) this week so I can do a reading of your KKmoon reference once I check my calibration.

It's not ideal but If no one answers your call with an in cal instrument PM me and I can help you out (you don't need to pay me, just pay for shipping).

[bitseeker]

Well I started reading the cal club thread with the Traveling Reference Concept, and didn't get all the way thru it, but I've sorta lost sight of the goal of it.

Probably better to discuss in the cal club thread, but in short, the current goals include (1) verifying that the roving standard is able to make the loop successfully and in good condition, (2) enabling members at each stop to do the measurements they want and provide some interesting info to the thread, (3) providing opportunities to learn enough to establish goals and improvements (hardware, software, process, etc.) for the next round, and (4) having fun.

[Bud]

There is also this AD588 board.. http://www.ebay.com/itm/111840217453?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It appears to have better tempco than the best AD584 reference I have.

Lets see....

AD588BQ:
Digikey - $49 Qty 100
Mouser - $47 Qty 100

Completed board eBay from China - $14 Qty 1

Yah... instills trust...Not.

[BU508A]

I've bought one of these (50 pcs of AD587LN) to play around with them:

http://www.ebay.de/itm/162254805543

It claims "SOCKET PULLS", but even in the ebay pictures you can see solder on the pins,
same on mine I've  received. I'll put some photos here this evening.

I'll also try to assemble a 10V reference in the Joe-Geller style (have the same parts as on his reference circuit)
but I have my doubts, that I'm able to achieve the specs of his reference.

Edit: Pictures added