[sdiy] MIDI-CV retrofit

[GGG]

Dear collegues,
	I need the expert advice! I'm about to add MIDI2CV conventer to my
DIY synth that, as most analogue synths, has CV and Gate controll.
	I built several desktop synths without a keyboard, where I used
external CV and Gate jacks with normaling switch lugs - when no external CV
or Gate is plugged in, CV and Gate from MIDI2CV conventer is routed to VCO
and ADSR correspondingly. When I plug in CV and Gate form analoue sequencer,
MIDI gets disconnected. That is easy.
	But with built in keyboard things are getting more complicated -
external CV and Gate jacks with switching lugs now disconnect CV and Gate
from the keyboard. So I added a switch that allows me to switch between
external CV/Gate and CV/Gate from MIDI conventer.

	But I wonder, if there is some more advanced solution to select
between controll sources, preferably automatically. I mean - when a MIDI
signal appears a device automatically switches to CV and Gate form MIDI
conventer and ignores signals from the keyboard. For CV I considered a DC
mixer - I just mix a CV from Keyboard, External CV and CV form MIDI
conventer. But how to manage Gates? Maybe someone has got across similar
case and can advice me a solution.

Thank you in advance!

Girts