[sdiy] First DIY synth (555 osc.'s)

[perpetual]

> > I wanted to build a bear bones system for more of a learning experience then
> > anything else.  I planed to build the VCO and ADSR from simple circuts I
> > found based around 555 timer chips and I was going to use CEM chips for any
> > or all of the VCA,VCF and LFO (if I included one).
> 
> Huh? VCO with 555, but LFO with CEM chip?
> 
> > I would use batterys in lue of a powersupply.
> 
> If you do so, use a VCO that is unsensitive to power supply voltage. Or
> you'll have to re-tune all the time when the battery goes weak...

so i was playing with a 555 oscillator last week.  more info here:
www.geocities.com/aurelialuz/shadow.htm

what i've found is that all this talk about instability is true.  this
thing is really temperature sensitive.  and we're not talking like a
couple cents over an hour, i'm talking like octave flucuations from
minute to minute.  this thing is powered off a battery too, so i've got
both demons of instability working against me.  if i was really
interested in creating some sort of stable oscillator, i'd look
elsewhere.

but lucky for me, i care not a whim for stability.  and what's really
cool about this thing is when you feed a wave output from another
oscillator into the CV input.  it becomes something like a sub-osc., but
instead of creating a low note, it gives all these weird overtones, sort
of like an "effects" oscillator.  

also, i've always read that 555's put out a pretty weak tone, but i put
a pretty big poly cap in it (.18uf) and i was suprised how thick it
sounds.  so if you go the 555 route, the bigger the cap the better.  

best,
alex