[sdiy] Thomas Henry XR-2206 VCO Page Up

[Scott Stites]

This past month Thomas Henry has been pushing the XR-2206 Function Generator IC to its limits to see how much musical use could be made of it for VCO purposes.  I breadboarded the circuit in parallel with him to confirm consistency from tweak to tweak.

The idea was to make it as simple as possible, yet be musically useful, so it's pretty low parts count.  It has a really nice voltage controlled skew function in it that sounds great.

We were able to get around 5 musically useful octaves out of it - it would be much better if the low end would have cooperated more, but we think that's all the XR-2206 would provide without running afoul of the law of diminishing returns - IE, it would start to increase in parts count/circuit complexity, which Thomas reasoned would defeat the original intent of the circuit (a very simple, easy to build VCO with some neat features).

I put up a page about it here:

http://mypeoplepc.com/members/scottnoanh/birthofasynth/id20.html

There are schematics, PCB layout, scope shots and one paltry sound sample.  I plan to expand the sample portions in my usual windy fashion, I just haven't had much time.  It sounds really nice through the Magic Smoke Mankato filter (but, then again, anything sounds really nice through that filter).  The VC Skew really plays well and gets downright mean with the resonance of Rene's Late MS-20 Filter clone.

Cheers,
Scott


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