[sdiy] Volt-a-meter

[Paul Schreiber]

> so whose meter is accurate? Whose method of measuring voltage is most
> accurate?
>
> I believe you that your MIDI->CV converter AND your meter is stable and
> predictable at that precision, but absolutely spot-on accurate, I'm not too
> sure of.

Well, what meter do you have? This is a HP34401A, which has been calibrated to 6 
1/2 digits of accuracy.
The calibration standard used is accurate to 8 1/2 digits. It was done on a 
Fluke 5520A, here is the link:

http://us.fluke.com/usen/products/5520A.htm?catalog_name=FlukeUnitedStates&Category=PMELE(FlukeProducts)

If you don't understand metrology, there is lots of info on the web. You may run 
accross the term "NBS traceable",
Google on that and learn some more. My point is: there is such a thing as a 
"voltage standard", and my meter can
whip your meter :)

And THIS meter kicks *everyone's* meter out the window:

http://us.fluke.com/usen/products/8508A.htm?catalog_name=FlukeUnitedStates&Category=CALMM(FlukeProducts)

>
> My question to the group is, at what level of precision do we (in sdiy) stop
> caring about accuracy? ie. if my meter says 1.0001 Vdc, and yours says
> 0.9999 Vdc do we really care which one of us is more accurate?

The average $50 DVM is fine for the vast majority of synthDIY work. But if the 
object of the project is to produce a *reference standard* MIDI-CV converter, 
then I want 6 1/2 digits. But that's just me :)

Paul S.