[sdiy] Back on the list - Guitar synth

[Mark Smart]

Hi all.
I just rejoined the list after being off of it for a long time.

In the last few weeks I have had another bout of "guitar synth fever" and am
working on my analog guitar synth board again. This is an ongoing project I
started many years ago and work on about once a year or so. The whole thing
is based around the old, clunky amazing Roland GR-300 with its blindingly
fast tracking. I decided to start trying to modify it to make more sounds,
so I have developed circuits to change its unusual sawtooth waves into pulse
waves (this is just an AD633 analog multiplier chip and a comparator) , and
to translate its linear control voltages (which are proportional to the
guitar string's cycle time) into 1 volt/octave CV's to interface with other
analog modules. I just got all six log converters wired up for the first
time yesterday. My log converter is based on the one from Electronotes
AN-114, but I used a 3046 and added a temperature regulator stolen from Rick
Jansen's Moog filter circuit (thanks Rick!). This works great because the
period-to-voltage converter described in AN-114 is very similar to the
GR-300's.

I now have this mad vision of wiring my GR-300-on-a-box up to a large MOTM
modular to make a polyphonic synth with filters for each string and pulse
wave capability.

Mwahahahaa....

I am interested from hearing from others doing guitar stuff. Also, if there
is a searchable archive for the list, where is it? That will keep me from
asking questions people have already answered (except for "Where is the
searchable archive?"). Thanks.

Mark Smart