[sdiy] DC vs AC in Audio/CV paths for hardwired synth.

[Dave Kendall]

Hi.

Hope this is not a dumb post(!), or one that's already been done to death,
but I haven't been able to get any opinions on this yet....
Hi all.

Are there any big disadvantages in having all DC signal and CV paths?

I'm in the planning stages for a relatively complex rackmount hard-wired
synth -  5 VCOs, 1 sub osc, 2 or 3 VCFs, 3 - 4 EGs, at least 2 waveshapers,
several triangle wave LFOs, a complex LFO, Sample and hold, several VCAs for
CV control and audio level, and (eventually) logic controlled
switching/routing and  PAIA/ELBY/uCApps MIDI control. Power will be a
Power-one Linear PSU, and most modules will be EFM/CGS, with a handful of
homebrew modules. 

I'm hoping to use CMOS switching IC's for the routing, and with 0V to +10V
max DC and audio, I could power these directly from the +15V supply, rather
than having to work out ±5V or ±7.5V supplies which would mean voltage
regulators, more bits, possibly a triple output PSU, compatibility problems
with some ICs, etc.. I guess it can be done, eg.
http://www.uni-bonn.de/~uzs159/switch.html>, but DC only *might* be simpler.

Would this be an advantage heat/power/space wise, or is there virtue in
having AC audio/CV signals?

I've noticed that some VCOs have DC outputs, and having DC LFOs/S+H etc.
would not be a problem.

Have I missed something really vital?

I've successfully built quite a few EFM/CGS modules over the last year,
being quite happy at the practical soldering and building stuff, but am very
poor on theory, having never really needed to study it until now, so
apologies if this is really basic stuff.

Any thoughts will be most welcome.

Cheers,

Dave