[sdiy] Useful equipment

[René Schmitz]

At 10:46 03.08.02 -0500, Paul Schreiber wrote:
>You guy's are doing it "backwards". You can get a cheap freq counter for $100 on eBay. As long as
>the VCO frequency is correct, the 0.000001V on the DVM doesn't matter. My Kenton Pro-2000 is
>about 5% off from my Encore Expressionist MIDI-to-CV, but who cares? :)

Well I don't know if this qualifies as "sdrawkcab", but the way I have been doing VCO calibration 
doesn't involve a DVM. I simply play octave jumps on my controller (usually a Midi2CV interface) 
doubled by another instrument, and bring the VCO in tune using the normal tune pot for the lower 
note. Then I calibrate the V/oct setting until the higher note is in tune. Then the cycle repeats, 
until the right setting is found. 

I also occasionally used a shortcut to this. I feed the VCO into a delay, whose delay time is the same as the octave jumps from my sequencer (via the interface). I mix the VCO with that so that both notes blend into each other. One can easily find the proper setting, as the octaves blending into each other have a characteristic harmonic sound. No need to touch the tuning pots to find the proper v/oct gain. Also it makes it easy to check that gain over the sweep range, by changing the VCO frequency manually. Or by going to two or three octave jumps.

However when calibrating the Midi2CV interface I used a DVM.

Cheers,
 René


-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159