DIY Ringmodulator for Analog-Synth Demo (Multiplizierer) erster Test

YouTube via Redled72
Googlish translation from German:
"Since I have a not insignificant amount of multiply (CAN metal housings, 1978, made in USSR) in stock (150Stück) had offered to develop a ring modulator / multiplication formally. A beautiful vintage-pot, similar to the MC1495/1496. I voted for him or Ux Uy one Summierer + inv inv Buffervestärker gegönnt. This means, switch all signals invers / noninvers create. There can be three audio signals can be created. Asymmetry within the multiplying means may be settling trimmer. Resting potential for Ux adjustable via potentiometer. The current / voltage converter OPV can be calibrated by means of adjustable offset and is externally frequenzkompensiert. In conclusion follows an OPV to decoupling. Error below 1% This part works perfectly, excellent symmetry behavior. I'm very satisfied. Can also be used as analog computers. The finished synth 3-4 of them will get gifts. Here is a superficial test with only 2 VCO! I had just not feel like a third VCO additional wiring in the wild on the board trying to build, even if it is for real bell sounds absolutely necessary. Obviously the board is once again hand."

Update via redled in the comments:
"I am the author of the Mudule=).
Check out my blog for Details of the Ringmodulator (german):
http://blog.redled.de/?page_id=149"
Googlish here