AW: Linear VCO Midi'ing?

Haible_Juergen#Tel2743 HJ2743 at
Thu Oct 10 20:15:00 CEST 1996

>I have the fine job <ackk!> of being asked to add Midi control to a Yamaha
>GX-1 synth. (formerly Keith Emerson's.)
>This beast has linear tracking VCO's and is very similar to two CS-80s for
>my purposes.
>I will not be supporting the pedal or solo voices.
>I've heard that Kenton has some linear version Midi to CV units for Korgs
>and CS-80s.
>Does anybody know more about these or other units? Do they make a Pro/4
>linear version?
>I have to control 16 voices and several channels of continuous controllers
>along with patch change capability (this might be the hardest part

So it's actually *polyphonic* Midi control for linear VCOs that you need ! 
I would highly recommend not to control the VCOs directly, but to connect
CMOS switches parallel to the keyboard switches (if it is in any way similar
to the CS- synths).
The old Yamaha polysynths have a strange type of matrix: not the usual
" 8 x something ", but an octaves-related "12 x something" matrix. I don't
know if Kenton has something like this.
But there is a solution by Doepfer: I bought a Midi Kit from them some
years ago to midify my CX-3 organ. It uses a long shift register and latches
to produce a gate signal for each separate note. There is also an option
with CMOS switches and level shifters that should fit into almost every
Prices were about DM200,- for the simple version, and about twice as
much for the CMOS switch version. These were the kit prices; As far as I 
they don't sell kits anymore. I have no idea if the whole thing is still in
In my CX-3 I only needed the basic version plus a single NPN and a resistor,
soldered across each key contact.


More information about the Synth-diy mailing list