Calibratory D-105 DC Precision Voltage Reference Standard

[codeboy2k]

Yeah that board looks nice.  Something like that is what I expect from a reference for sale.

To be clear, this is not a 10V reference, nor is it trimmed. It is however, well built.

He's using the REF102 untrimmed, and some OPA2141's for gaining the 10V output to +/-14 Volts

The OPA2141 has max Vos=3mV. This is used on the +14V output, and there is another one that simply inverts that for the -14V, which adds another 3mV offset.  From the datasheet, OPA2141's are 0.14ppm/C @ 14V output, that's not bad.

The REF102 is 0.1%, which is 10mV. The first OPA2141 is gaining up the Ref voltage and the Ref error and the opamp Vos of 3 mv by 1.39. That's 1 + 0.39 because it's a non-inverting op-amp. The 0.39 part is due to the divider resistors, and if using 0.1% divider resistors on the opamp, then the gain error could be ((4k7*1.01)/12k) - (4k7/12k) = 0.39%.  So the 0.39 part of the gain equation could be off by .39%. 

So the max gain will be 1 + (0.39 * 1.0039) =1.392
 (10 + 10mv + 3mv ) x 1.392 = 10.013 mV * 1.392 = 13.94V.

Op-amp input bias is in the pA range, so let's ignore it.

Finally, for the -14V output, add the 3 mV Vos of the second OPA2141 in inverting unity gain, for a maximum output of -13.97V. 

final error is |(13.97 - 14)| / 14 = 0.21%

So there you have a +/- 14V DC reference, which you can only say is 0.21% absolute accuracy. Let's be conservative and say 0.25%

It's still not bad though, for a +/-14V reference. Too bad the way they designed it, the +14V does not track the -14V exactly.

[Excavatoree]

Thanks for the analysis.  I meant that the implementation was very impressive, not that the device itself is functionally equivalent to any other device.    I should have been more clear.

[HighVoltage]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

[TunerSandwich]

I make no claims regarding long-term drift of the D-105 DC, except 2.5ppm/1,000 hours of use. If you don't like it, I apologize, but that's just the way it is. I am not required to supply proof for claims I DON'T make! But that's only common sense; at least to me it is.

" Long-term  drift is <1.5ppm/1,000 hours of use, and decreases with age."

quoted DIRECTLY from your eBAY ad.....

OK, I forgot to update that listing with the new figures. I implore God's Mercy upon me: that you be smote, because you have no respect for others. I pray that God Almighty get you out of my way, today! You earned it.

Just in case anyone missed it......

also just in case anyone missed his "math"......of the statement of "2.5ppm/1000 hours"......or the statement of "I don't know what the long term drift is".....

by his own statements (which he clearly doesn't understand)....the long term drift is 21.9ppm / year......

That is actually WORSE than Ti's own findings......so, since there is NO data to show what HIS device does over time, and he makes the wholesale statement of "2.5ppm/1000 hours".....then we have to assume it's 21.9ppm / year......and that is simply awful   

let's ignore the facts that he can't even follow Ti's recommendations for calculating actual drift over time.....(trust me it's really NOT 21.9 ppm / year).....but by Awesome14's "logic" and lack of testing....that's what he is claiming.....

[JohnnyBerg]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.

This really looks like crap. And I was worried my reference was not good enough to sell. 

[timb]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

File a claim with PayPal requesting a refund. One stack is a lot to wast on $10 worth of parts and bad soldering. (Unless you see $90 worth of magic in there!)


Sent from my Smartphone

[TunerSandwich]

Honestly it doesn't matter what something "looks like".....

What matters is that it performs to stated specifications....

I wouldn't care at all if someone sold me a "ref" that met it's stated figures, but looked like a festering pile of dog turd.....

But it looks like with Awesome14's "product" we don't get either one......

I would focus less on the looks and more on the shoddy parts (aside from teh ref102c) and the total lack of data, and outright lies being told about the product.....

Hell I could even put up with the wacko talking to angles crap if it simply had stated specs and met those specs.....

what do you guys think of this circuit? 

[timb]

If it works, it works. However, in this case I have no confidence in Awesome14's abilities. I've seen some pictures of Jim Williams breadboard circuits; sometimes he just soldered components together wire to wire in a big ball, hanging in the air by BNC cables! He got amazing performance out of stuff like that, but they were prototypes and not meant as a saleable product.

In this case, it's not *just* the look of it. It's the fact Awesome14 hasn't provided any data along with the hobbyist construction and talking with God stuff. It would have me getting my money back. 


Sent from my Smartphone

[HighVoltage]

I had it hooked up to my 34461A and after turning it on, the voltage started at 9.9970 Volts and made its way up smoothly to 10V
But when I moved the unit slightly, the voltage was jumping all over.
May be some god inspired awesome solder spot came loose?
Who knows, I do not care anymore.

I filed a claim with ebay / paypal and may be I will be lucky and get the money back.

[Terabyte2007]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

Quite embarrassing isn't it? It was a gamble, but I am not going to get too upset over 99 bucks because I knew I was taking a chance when I purchased it. So hey, I am trying to be optimistic and just move on to the next! I may be able to make chicken salad out of this chicken shit somehow!

[lowimpedance]

But you won't be bothering me much longer, because I've asked the Owner of The Universe to clear you out of my way. 

Now that has to be the quote of the week 
Gotta use it at work  !.

[TunerSandwich]

I remember seeing these on eBay long before this thread.....and I considered buying one to test, until I noticed zero data.....no pictures of internal construction....and then read the totally conflicting seller description.....I had a laugh over it, but am a bit surprised that others took the bait. 

I feel bad for you guys that had to invest you time and money into this thing.....but as you guys said, it's not like you blew some huge bankroll on it.....

what immediately threw up a red flag for me, upon first viewing his item was this statement in the description "Years ago I wanted something cheap and portable--even implantable--to calibrate hand-held DM meters. "

 

also this gem

"Over a series of years the design has added filtering, noise cancellation, thermoelectric-effect suppression, high-granularity trimming, temperature compensation, dynamic settling, high-accuracy output, low drift, silicon aging, miniaturization, output jitter-damping, resistive balance, safety features, and excellent repeatability. I have a scientific background, so I just had to learn the analog application side. I aimed at the amateur market, because calibration labs were treating them poorly! Now they don't need them! "

claiming not to need a cal lab?  but isn't he a "cal lab"?  And if not then why would I want something that didn't rely on a cal lab?  That means it's performance is unknown.....

and the real nail in the coffin...."jitter-damping"...... .....because we all know about the problem of output jitter in an analog REF

in case no one caught that....let's see it again "jitter-damping"......someone has been reading too many hi-fi magazines

[HighVoltage]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

Quite embarrassing isn't it? It was a gamble, but I am not going to get too upset over 99 bucks because I knew I was taking a chance when I purchased it. So hey, I am trying to be optimistic and just move on to the next! I may be able to make chicken salad out of this chicken shit somehow!

Same here, I am not upset about the $$.
It is just sad, that such people exist.

[Awesome14]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

Let's be fair. You took it apart and broke it! You had no practical reason to disassemble the unit. If you hadn't done that, it would still be working perfectly! The unit arrives sealed. There is no reason to open it. You can understand that.

[Awesome14]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

Quite embarrassing isn't it? It was a gamble, but I am not going to get too upset over 99 bucks because I knew I was taking a chance when I purchased it. So hey, I am trying to be optimistic and just move on to the next! I may be able to make chicken salad out of this chicken shit somehow!

Same here, I am not upset about the $$.
It is just sad, that such people exist.

It's even more sad that people intentionally break stuff, blame the manufacturer, and then say it's sad that the manufacturer exists.

[Awesome14]

Unfortunately, I was one of the first one to buy this crab, long before the first pictures emerged.
The unit arrived today.

Here is my little tear down and the pictures.
The soldering looks like it was done by a hobbyist that just started his new hobby and tested on a few spots.
Some stranded cables have some strands looking out and almost touch other connections.
It is horrible from any aspect of engineering.
It is even horrible from a hobbyist point of view.

I would never have bought it, after the first pictures got shown here.
But, well, I have it now.
I will hook it up to my 34461A, just to get some data and see the performance.

OMG, what did we get in to.

Quite embarrassing isn't it? It was a gamble, but I am not going to get too upset over 99 bucks because I knew I was taking a chance when I purchased it. So hey, I am trying to be optimistic and just move on to the next! I may be able to make chicken salad out of this chicken shit somehow!

I'm not the least bit embarrassed, because the performance is stellar if the user doesn't break the unit. Truth will win out in the end. What was Truth is Truth now, and it always will be Truth. There is One Truth! Everything else is w-r-o-n-g !

[c4757p]

Will you just shut up already?

[Excavatoree]

The construction didn't magically change when it was opened.  I hardly see how one can justify poor construction by blaming the person who discovered it.

[rx8pilot]

If the unit is damaged by taking the cover off, it's not a product. Period. End of story.

I have adjusted and repaired many thousands of boxes over decades. Not once did they ever get damaged when I pulled the cover off.

It is not only reasonable, but expected to be able to take apart for basic service and calibration.

[EEVblog]

The construction didn't magically change when it was opened.

This is clearly Schrodinger's Reference!

[Awesome14]

The construction didn't magically change when it was opened.  I hardly see how one can justify poor construction by blaming the person who discovered it.

The construction of these units is superb. There is nothing left to chance. Causing a defect + simultaneous discovery of the defect = causing the defect. If the unit was defective before it was sent out, it wouldn't have been sent out. All units are thoroughly and exhaustively tested before shipment. It is possible one could still slip through, but when the defect is caused after the device leaves our custody, and the user disassembled the unit, the user is at fault.

Regardless of how many times you voice the same wrong thing, it will never be true. I don't know why, but the more I extend a voice of reason, the more some members of this board adopt a stance directly  opposed to reason. It simply is not rational to assume the fault lies with a conscientious manufacturer who has nothing to gain, when the user has posted photographs  to prove he opened the unit and thereby ruined it. For all I know his interconnects are bad too.

Many of you assume the worst about everything. You judge by appearances without regard to substance. You seem unable to speak fairly, always resorting to unfair play. Is there any reason why some of the members here act like their lives depend upon disparaging a perfectly good product simply because your prejudices cannot reconcile any viewpoint other than your own.

I am not to blame for anything here. I'm allowed to believe what I please and to share my beliefs in a public forum. Why keep attacking? You only mire yourselves in guilt for doing intentional harm to the innocent.

[c4757p]

The construction of these units is superb.

Really, does anything more need to be said? This is high comedy.

[rx8pilot]

like they say....A picture is worth a thousand perfboard holes.

[Awesome14]

If the unit is damaged by taking the cover off, it's not a product. Period. End of story.

I have adjusted and repaired many thousands of boxes over decades. Not once did they ever get damaged when I pulled the cover off.

It is not only reasonable, but expected to be able to take apart for basic service and calibration.

Your wrong! There is no reason to ever disassemble the unit, even to calibrate it! No matter how many times you say the same wrong thing, it will never be true. I'm the manufacturer. I say the unit cannot be disassembled by the user. If the user does so, and the unit malfunctions, it's the user's fault  for disregarding the obvious seal on the product.

Believe it or not, most people do not buy a voltage standard and then take it apart! News Flash! Most people leave it together and use it for its intended purpose. But I never could have anticipated what I found on this board. If I would have known the horrible injustice that awaited me, I would have just bought real estate! But NOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!! I had to try to do something truly good, to add something to the world, to actually help the very community you meddlers occupy!

It may seem strange to some of you here, but I can easily  afford to take a bulldozer and plow my voltage-standard enterprise into a landfill. After meeting the problem children on this board, I'm thinking about it. I have met here the rudest and most unreasonable people I have ever met in my life. And that is saying a lot! Your tactics are those of abject wickedness! You have a corrupt agenda, and you follow it no matter what the cost.

I think it's sad that a few members on this board piss away your pathetic lives bent on destruction rather than production.

[c4757p]

NOOOOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!

Oh my god dude shut up. You read like you're hyperventilating. Go breathe into a bag or take some pills or something.