[sdiy] Required modules to make the most basic sounds??

[Andrew Dixon]

I am just getting started in this homemade synth game, and I don't want to
get to far in over my head (or beyond my wallet!)  So what I would like to
know is what modules I *have* to have to start making some sounds (no matter
how basic those sounds are.)  The way I see it, from what I can tell from
the reading I have been doing recently, is that I would need the following:

VCO (or alternatively a noise source)
envelope generator
VCA
and something to generate control signals

I would really appreciate it if anyone on this list could confirm this for
me or correct me if I am completely on the wrong track.  Any comments would
be great!

Andrew