Something like Motu Volta or Expert Sleepers Silent way

infuzion · 11 Nov 2011

Welcome to SM stahlblau! What is the resolution possible if you used FlowStone hardware?

rl · 11 Nov 2011

Interesting concept. If I understand that right, the audio outs of a soundcard are used as control voltages for an analog synth. I think that wouldn't work with any soundcard, since a control voltage is rather DC than the AC of a soundcard's output. If a soundcard is able to handle that, I think it's just a matter to send audio to an output channel and should be doable with SM. Or you need a special analog interface like a Doepfer Dark Link, which builds control voltage from midi signals (also possible with SM) (http://www.doepfer.de/Dark_Link_e.htm). Lot's of creative usages come into my mind, e.g. applying delay to the audio signal or the rhytmic texture of a drumbox sound to control the pitch of a synth.

(Long time ago I used a cheap casio vl-tone to control my Korg MS-20 for unbelievable strange sounds, but that's a different story)

trogluddite · 11 Nov 2011

This is relatively easy to test - you just need a cheap multimeter. From SM/FL you could just make a schematic to send a continuous value of 1 to a soundcard output - or use the wave drawing tools in a DAW to generate the same thing. Then just measure the voltage across the terminals of the soundcard output.

I imagine that most soundcards will be AC coupled, in which case you would see a short pulse when the signal hits the soundcard that will quickly decay back to zero. But it's possible that some cards are DC coupled and will hold the voltage - though I would guess that is more likely for expensive high end cards.

If the voltage is held, you will probably still need some ibuffering electronics between the soundcard and the analogue gear - partly to get the voltages into the right range, and also to prevent too much current draw from frying the output stage (many soundcard outputs are designed to run into a very high impedance; i.e. not much current available). The circuitry needed would be very simple, and much cheaper than a proper interface board - there are many examples of op-amp driver circuits available on the net.

There's a thread on KVR about DC coupled soundcards HERE that you might find useful - like I say, mostly 'Pro' cards - but it maybe it will point you to something you could buy at a reasonable second-hand price.

Another possibility, if you (or someone you know) have the electronics knowledge, would be to buy a very cheap, bog standard card, and bypass the AC coupling stage. This often consists of nothing more than a single capacitor (plus a drain resistor sometimes) in line with the output socket. Soldering a small wire to short out the capacitor should leave you will a DC coupled output. Of course, if you try this on something expensive and break it, I will deny ever having given you that advice! 😉