From colin@octavo.demon.co.ukWed Feb 15 12:48:55 1995 Date: Wed, 15 Feb 1995 21:06:02 +0000 From: Colin Fraser To: Peter Sansom Cc: analogue heaven Subject: Re: SH 09 Mods... Hope this gets through hyperreal ok... On Wed, 15 Feb 1995, Peter Sansom wrote: > Being the owner of two SH-09 's I was wondering if they can be modified > to allow external axcess to the filter , LFO etc. I modified my Sh09 to allow external control over the filter and oscillator and it was pretty easy. The modulation lever is a variable resistor with +ve and -ve voltages at either end and the wiper connected to the mixer that varies modulation depth to the filter and oscillator. I routed the wire from the wiper to a jack mounted on the plastic end cheek, then back to the mixer circuit, so when a plug is inserted it breaks the connection from the lever and gives variable external control over filter and oscillator mod. I also added a distortion circuit between the filter and vca (which makes some wild noises...). I soldered the input and output of the distortion circuit into the holes for the decoupling capacitor between vcf and vca, and mounted the circuit inside the right hand end cheek. I wouldn't recommend trying this until you're a bit more confident with electronics. If you can find someone who knows what they're doing you could always ask them to help, and maybe throw in a quick lesson. The Sh09 is a great synth to work on tho', each module is clearly outlined on the pcb and it isn't too fiddly to take apart and put back together - I always like a synth that doesn't need all its knobs pulled off before you can get at the circuit board... Peace Cf