[sdiy] modern AD/DA chips?

[Tom Wiltshire]

On 7 May 2009, at 10:21, Tom Arnold wrote:

> On Thu, May 07, 2009 at 09:22:17AM +0100, Tom Wiltshire wrote:
>> Sorry if this seems like pointing out the bleeding obvious, but how
>> do you know the errors are all in the MIDI->CV?
>
> Simpler to check then you think. :-)
> If I drive them all with the same CV, they stay pretty amazingly  
> close in
> unison.   Its when driven from seperate CVs that the error rears  
> its dead.

Ok, that seems pretty clear.

> Anyhow, in this particular case I was seeing very predictable  
> errors on the CVs
> themselves.  When you should see, say, 4vdc on everything, and you  
> see 3.996
> 4.000 and 4.004, and all that happens is the numbers stay the same  
> but move
> around, yeah, thats your DAC :-)

Could it be reference voltage drift that's making all the DAC  
channels drift together like you describe?

Just an idea. I'm fishing for other possible causes here. Again, it's  
a easy one to check.

Regards,
Tom