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

[Thom Somneevich]

----Original Message Follows----
From: perpetual <perpetual at uswest.net>
To: synth-diy <synth-diy at node12b53.a2000.nl>
Subject: Re: [sdiy] First DIY synth (555 osc.'s)
Date: Mon, 07 May 2001 09:37:08 -0700


 > > 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

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com