Tom G's VCO-4d is working

[Roy Tate]

I haven't heard anything either way from other builders, so I 
thought I would chime in.  Tom G's VCO-4d worked fine for me.
I went with the tempco option, and it worked as advertised.
I haven't fully calibrated the V/Octave scaling, but the saw,
tri and sine look good.

A few observations and a stupid mistake I made:

1.  I tested it as a bare board, so I had to clip a jumper
    from sync-in to -V

2.  I first tested it with an init-freq that tuned the VCO
    way above audio range, so I was disappointed with the
    wave shapes and the low output drive.  I realized my
    mistake when I plugged it into my modular and heard 
    nothing.  After fiddling with the init freq, all of the
    wave shapes started looking good, and I started hearing
    some sounds.  :)

3   By the way, you won't get a square wave until you wire up 
    the pulse width pot.

Some of this is obvious from the circuit, but a little 
repetition can't hurt.

While I'm here, is R30 supposed to be 100K or 1K?  R30 is the
sawtooth output resistor, coming off of U2.  Most circuits I've
seen take the low output inpedance route.

Regards,

Roy Tate
roytate at ionet.net
http://www.ionet.net/~roytate