[sdiy] +/- 9v synth circuits

[Stephen Lenham]

A few suggestions:

- Don't abandon the 2 x 9V battery idea too soon. As you've already 
identified, you only need a stable supply voltage for a few critical 
tuning-related parts, and these parts are not those which require a 
large headroom. So why not create a low current regulated supply at, 
say, +/-5V for these parts and run the rest of the unit on raw +/-9V?

- 9V battery does not automatically mean PP3s (Duracell PP3 = 550mAh, 
by the way). You can still get the much bigger PP9s if you look for 
them (don't know the capacity, but suspect several Ah)

- Check out the original Practical Electronics Minisonic (not the 
Minisonic 2, which is a more conventional keyboard based unit) if you 
can find the article anywhere. It was very much what you say you'd like 
- a portable (compact square wooden case with mini stylus keyboard) 
semi-modular (many signals brought out to front panel minijacks) 2-VCO 
synth designed to run from two 9V batteries.

Hope this helps.

Steve L.

> Thanks for the ideas guys! (spec the part about
> headroom) How about this, two 9v's in series per rail
> into 7812's,that will give me the headroom for the
> regulators even if the bat's go a little flat correct?
> The only reason I'm thinking about regs is for tuning
> stability. The wasp idea is a good one too, iirc
> someone was thinking about cloning one of these with
> midi as a commercial project. The main reason for
> using batterys is for my commute to school (no outlet
> on busses)and the fact that I hate wall warts. I am
> shooting to make this thing semi-modular (ala evenfall
> minimodular, I have one and it rocks). If the 4 9v's
> and regs can do it I may just build up the madmouse
> board ive had forever and save myself some dough.
> Two more questions, how can I figure the max current 2
> 9v batts in series can give me, and does anybody know
> how much current a madmouse (the non-midi one) draws
> per rail?
> 
> Once again I'm amazed at the mass of knowledge on this
> list.
> 
> 
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