LVM, was Re: [sdiy] PIC Quantizer project

[john mahoney]

----- Original Message ----- 
From: "Grant Richter" <grichter at asapnet.net>
>
> That is the Serge scheme. Control is 0 to 5 volts and audio is +/-
2.5
> volts. You still use 1 volt per octave with a 5 octave range.

Well, look at that. The Serge scheme is practically made for hybrid
synths. :-)

In addition to +5 and Ground, I could see having standard +2.5
and -2.5 signals available throughout the synth, for level shifting
purposes.


> The Synthi and Putney use 0.325 volts per octave (IIRC) in the patch
bay.
> All the signals are bipolar +/- 2 volts including the envelope
generator.
>
> It works OK, but has more hiss than higher voltage systems like ARP.

Is this is a symptom of older components? Home hi-fis use, what, 1V
ptp for line level signals? Yet, my hi-fi is not hissy.

I had assumed that modern components were accurate enough to work well
at lower levels, and here Serge synths have been doing it for years.
Make that decades. So, I really don't see a need to use +/-10V or even
+/-5 in the 21st century.

Thanks a lot, Grant!


Ray Wilson's Sound Lab Mini-Synth runs on +/-9V (2 9V batteries), so
at least one person has developed low power synth circuits. The Sound
Lab uses 442 op amps, which are very low power; Ray even said that he
might redesign some of his other circuits to use the 442.

The noise specs on the 442 (and 444) aren't very impressive, though.


Plenty of food for thought. Time to digest a little...
--
john