[sdiy] +/- 9v synth circuits

[harrybissell]

If I had to do a +/-9V synth... I would study the "Wasp" synthesizer for ideas...

I'd do a high frequency VCO with a programmable digital divider...  now tuning
stability is not really an issue... all the notes will always be in tune.  I'd
add the Wasp
filter and whatever else you like.  I would not use voltage regulation at all for
most
of the circuits... possibly just some reference voltage IC for the VCO

I would not try and copy the Wasp's PLL trackers... otoh if you need portamento
that would
be a way to go.  If you kept the HF-VCO quite high in frequency... you could
locate the
PLL high up in the chain (higher freq. input will make the PLL settle faster...)
For waveshaping
I'd use digital dividers and summing resistors... maybe a 16 step staircase
instead of a sawtooth...

H^) harry

Scott Gravenhorst wrote:

> I would not use regulators with batteries.  Linear regulators "waste" some
> current while doing their job which will shorten battery life and the work
> done by that waste current only makes heat, not music.  It's pretty hard to
> find a place to play (except perhaps "out in nature") where there isn't a
> place to plug in.  If you go with a wallwart supply, you can do +/- 12 or +/-
> 15, the headroom there is a good thing and these are easy to make regulated.
>   If batteries are a must, I would select batteries that have a good
> discharge curve.  Someone will correct me if this is wrong, but I think
> alkaline batteries have fairly constant voltage output until near the end of
> their life when it drops rapidly.
>
> >> -----Original Message-----
> >> From: owner-synth-diy at dropmix.xs4all.nl
> >> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Ryan Guilfoyle
> >> Sent: Tuesday, December 02, 2003 10:56 AM
> >> To: synth-diy at dropmix.xs4all.nl
> >> Subject: [sdiy] +/- 9v synth circuits
> >>
> >>
> >>  Wondering if anyone can give me some insight on a
> >> project I'm working on. I'm trying to make a small 9v
> >> battery powered synth, for open mic nights/use at
> >> college. It does not need to be very complex or
> >> expensive, only portable and stable tuning wise. I've
> >> already got an LFO/AR and some cv processing circuits
> >> working on +/-9v, the main problem I see is making a
> >> making a multimode SVF, and a VCO. The synth does not
> >> need to have more then a 3-4 octave range on the vco's
> >> ect.. My planned config is 2 pulse/tri vco/2 lfo/ 2
> >> env/ 3way mixer/MM vcf/lag and S&H/noise and 2 vca's.
> >> I have a bunch of EFM boards I thought I lost in my
> >> last move, and it would be very nice if i could get
> >> them to run on +/-9v.I will be following the bat's
> >> with voltage reg's. Any pointers tips ect.. would be
> >> greatly appreciated.
> >>
> >>
> >> __________________________________
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> >
>
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