mixer/multiple circuit?

[Nikmis]

what do people recommend as the best and easiest ways to make a 3-in mixer with 3 outputs thats good for preserving control voltage signals, like pitch CV, as well as audio? it doesn't seem too far out to me, but i couldn't find anything anywhere.

[crashlander42]

I built the 1u and 2u audio/CV mixers from Yusson's site last week and I'm just as pleased as can be with them both. I've used them both for mixing audio as well as CV and they've worked fine. If you wanted more outputs on it you could always add a distributor. Which is the module-next-door on my synth.

[Dave Kendall]

Hi.

These are very useful, and small too......
They've got 2 outputs not 3 though.

[Nikmis]

I was thinking of both of those, actually. But with the CGS mixer, would adding an extra output affect the circuit at all? with the Yusynth Mixer/Mfos distibutor combination, I suppose I could use them both together. They are simple enough, as well. And the yusynth and cgs schematics are pretty much the same, just the opamp setup, and then another because its inverted.

so that part is ok. but here is probably a dumb question; Does the MFOS distibutor work fine for audio as well.

[Funky40]

[goldenechos]

HIgh precision CV summing can be tricky. The op-amp choosen can have an impact on accuracy. You need something with low input bias and offset currents. I have seen the TL072 used with good success.
Try a combinationn of a resistor and low value trimmer in the feedback path of the second opamp so that you can trim to exactly 1V/ oct. (if that is what you are summing). If you are concerned with droop due to tapping multiple outputs I would suggest non-inverting followers (again, low input bias and offset currents) on each tap.

Probably you CV ins are fairly high impedence though, and the combination of that with the option to trim in more gain should set you up nicely.

TR