[sdiy] CV from soundcard

[Paul Schreiber]

You are probably *not* going to be able yo hack just any soundcard for Volta 
(I mean, part of the reason for Volta in the first place is to sell more I/O 
cards).

I'm sure as Volta gets more and more tinkered with, there will be at least 
10 websites about 'Volta compatible cards' and ' Is your your card hackable 
for Volta?".

Meanwhile: here are the issues

a) Many sigma-delta DACs used for audio output are *specifically designed* 
for no DC offset (what Volta is forcing). Chip designers spend 100s of hours 
making sure their designs have minimal DC offset.

b) the card designers add external DC offset correction, can be as simple as 
a big (say 220uf) cap in series with the output or a fancy DC-Servo loop.

c) dynamic range issues. If my synth wants 1V/Oct output how can a sound 
card, that is specifically designed for audio at 2V pk-pk full-scale going 
to do me any good?

Volta is a clever app, but it is an app *designed* to sell you a *new* I/O 
card :)

Paul S.