[sdiy] why +/- 15V

[Cornutt, David K]

From: René Schmitz [mailto:uzs159 at uni-bonn.de]
> 
> Next question: Why 10V signals? :-) This is more of a hen / egg thing 
> IMO. A 0.1V/oct and 100mV signal level would do also.

Given that we're talking about the early '60s,
I think that control signals with levels that low
would have picked up too much noise, making
VCOs unstable.  I'm guessing Bob Moog went with
the 1V/octave standard because it worked with
the supply voltages that were commonly used in
those days (generally higher than most electronics
use now) and it was fairly easy to measure with
a decent analog voltmeter and/or scope.  Certainly,
some other ideas were tried.  EML's notorious 1.2V/oct
scale actually makes sense if you look it in terms
of semitones: it's 0.1V/semitone.

The lowest CV scale that I know of is the 0.3V/oct
that EMS used.