Moog modular ring modulator w/ transformers?

rjd2 · Joined: Sep 02, 2007 Posts: 226 Location: philly

hey folks, i stumbled across this ebay auction:

http://www.ebay.com/itm/Vintage-Ring-Modulator-Unit-for-Moog-Modular-System-Analog-Synthesizer-Rare-/170957157600?pt=Keyboards_MIDI&hash=item27cdd734e0

and realized that it uses UTC A-20 transformers. i actually have four of these lying around doing nothing at the moment. did some googling, and i cant find much info on this original module; im thinking if i could find the schems, maybe i could duplicate it? looks like mostly diodes and transformers. anyone have any info on this by chance? thanks, rj

JingleJoe · Posted: Fri Dec 14, 2012 1:42 pm Post subject:

9 out of 10 of the "proper" ringmods I've seen are this circuit
http://petemoss.org/bending/ringmod.jpg
That's probably what you've got there Smile

rjd2 · Joined: Sep 02, 2007 Posts: 226 Location: philly

thanks!

JingleJoe · Posted: Fri Dec 14, 2012 2:29 pm Post subject:

I prefer this kind of circuit layout though
http://www.3amnoise.net/ringmod.jpg
I like it when the diodes in a full wave rectifier form a diamond shape Laughing

note: just noticed they have different inputs and outputs ... I want to get an oscilloscope on that and see what the difference is!

analog_backlash · Posted: Fri Dec 14, 2012 4:10 pm Post subject:

That last diagram looks suspiciously like Ken Stone's diagram Wink

http://www.cgs.synth.net/modules/cgsrr.html

Finally got link to work properly. Having trouble doing things in Google Chrome!!!

I'm only bothering to say this as Ken gives a bit more info on the circuit here, such as using Ge diodes (or Schottkys) and the need to match them.

Gary

ADDITIONAL: See the e-m thread:

http://electro-music.com/forum/topic-28218.html&postorder=asc

Which covers the CGSRR and other transformer/diode type ring mods.