synth-diy

[Johan Gustavsson]

> im interested in building my own synth equiptment. what is the best way
to
> get started? i dont have experience with this sort of thing but am very
> curious...

I'd recommend, as I always do, TomGs "Electronics for music" site for
actual, practical circuits. http://www.mindspring.com/~vco

Work is now finally underway on the Moxie Maxx Modular, and so far (as
of today) we've built one ordinary boring dual LFO and one simple VCO
(the LFO-1A and the VCO-5A). Tomorrow we'll do the VCF-8b (the dual
KLM one) and go looking for a good box to put it all in, as well as
finish the PSU. Now, the point of this is that both I and my building
friend are relatively new to this building thing, and have access to a
good soldering pencil, a couple of multimeters, a scope and nothing
more. We etch circuit boards one by one, using layouts made in MS Word
of all amazing programs transfered to plastic film. Can you say
"budget"? And they both worked first thing when we plugged them
in. Sure, they are both relatively simple constructs, and I haven't
yet tried the vco with a proper 1v/oct CV source, but still - We
turned on the power and got nice squares and triangles on the scope,
reacting the way they ought when we turned the pots. Amazing enough
for me :-)

My initial meterings seems to indicate that the VCO isn't responding
in quite as linear-ish fashion as I'd like -

-11  v from the pot	-   90 hz
- 7.5v			-  180 hz
- 4  v			-  352 hz


...and so on, which doesn't bode well - Any hints? Then again, this is
when just plugged in, lying flat copper side down on the
(nonconductive, silly!) workbench, with an amazing juryrigging of test
cables and little croc clips providing power and connecting to scope
and meters, with no input except the tuning pot connected, so perhaps
the conditions aren't quite ideal...:-) We might scrub the solder side
with a toothbrush to get of solder flux goo tomorrow, as well as maybe
scrounge up some heat conductive paste and press the expo trannies
together - Think that would help? My plans for this one isn't
acutually to be a "voice" osc, but rather a modulation oscillator in
the higher frequency range, so in the end I probably won't mind too
much. I'm planning on building the VCO-2s as main voices. and started
off with the simpler stuff just to get a feel for it. Make it up as
you go along, y'know. :-)

At the same time, whilst waiting for the photoresist to dry, I opened
up the broken filter env amount slider on my CS-01, cleaned it, put it
back together and - Whoo! It is a whole new instrument! Now I only
wish that the amp env amount would fade between an envelope shape and
something gateish instead of just acting as a second volume control...

Anyway, today has been a good DIY day. Hear from you again tomorrow
:-)

/Moxie (Happy builder)