modifying old soudcard to output DC?

[dentaku]

I know this sounds a bit strange but...
Does anyone think it's possible to modify an old soundcard (PCI SoundBlaster etc.) so that they output DC?
I have some old soundcards lying around and the real Creative Labs one has some regular electrolytic caps on it so if one of those is a decoupling cap for the output it seems like I might be able to short it and have the output send DC.

At the moment only professional MOTU audio interfaces seem to be DC coupled.

[garak]

Yes, this is certainly possible, and people frequently do it. Without seeing your specific card I can't say which exact capacitors you would need to bridge, but I doubt they'll be electrolytics. My money's on ceramic SMD jobbies. Trace the signal lines from the jack back to the DAC, you should be able to find them without much hassle.

[dentaku]

Since it's a SoundBlaster Live! CT4830 I was hoping the output was using the easy to modify through hole Nichicon caps but of course I'm just hoping it's those because they're easier to work with


We'll see. I guess it will be a learning experience for me to track down the path to the line-out.
 

Yes, this is certainly possible, and people frequently do it. Without seeing your specific card I can't say which exact capacitors you would need to bridge, but I doubt they'll be electrolytics. My money's on ceramic SMD jobbies. Trace the signal lines from the jack back to the DAC, you should be able to find them without much hassle.

[tszaboo]

I would rather build a peak detector circuit, and use that to create DC signal from a soundcard. Output a 10KHz signal, volume is the DC.

[dentaku]

When I watched this video a while ago I wondered if it would be useful for creating control signals for a VCO.
http://www.eevblog.com/2013/06/29/eevblog-490-peak-detector-circuit/

It would still be great to modify an old unused soundcard and use it to control a VCO though. It's just to experiment with something similar to MOTU Volta.
http://www.motu.com/products/software/volta/body.html

I would rather build a peak detector circuit, and use that to create DC signal from a soundcard. Output a 10KHz signal, volume is the DC.