Archive of the former Yahoo!Groups mailing list: MOTM

Paul, I finally got twenty minutes to myself last night to fire up the VCO I
built a month ago. This was just a bench-test-by ear-I didn't calibrate it
or use it in a musical context.

First of all, it passed the smoke test. Hooray! I guess I followed
instructions! That was my first concern-no fires and please please please
let ∗sound∗ come out of it!

In a nutshell, everything worked. You know that you're an analog synth
addict when you can entertain yourself for long minutes by manually spinning
the Pulse Width knob back and forth, grinning at the sound. Same goes for
pitch sweeping the VCO.

The tuning controls on my unit sound perfect to me-no scratchiness or
uneven-ness at all. Very smooth sweep. Using just my [thirty-something] ear
and a small speaker, it sounded to me that the Coarse tune control puts the
output supersonic at about "8," and subsonic below around "3". When I use
bright waveforms such as a sawtooth or narrow pulse, I can hear the upper
harmonics go "tick...tick...tick..." even when the fundamental has gone
way-far south. Very nice range. And like I say, smooth sweep.

The Width control seems, by ear, to have almost a 'flat spot' around 50%
where the pulse sounds square even with a little play in it. In other words,
it sounds square from around 47%-53% on the dial. Maybe that's just my ear,
or maybe that's intentional. It works out well, though. I also notice that
the Width control doesn't go to "100%" or "0%" where the sound would
disappear at either extreme-it stays just inside of the margins of
audibility. I imagine applying PWM would push it over the edge if desired,
but the knob covers a good comfortable range. Very nice.

Anyway, sorry for the delay in getting back to you with this report. Chalk
up one more very happy camper! I'm eager for my next shipment!