Gonkulator / 1496 ring modulator

[Tim Escobedo]

I'm guessing U3A and U3B are the oscillator, though pin 6 and the 15pF cap look weird. The back to back diodes connecting the oscillator to the 1496 may be some rudimentary sine shapers.

And U4B is the distortion section for the "dry" signal. Jumper the 10k resistor in the feedback loop, and it'll go from clean unity gain to distorted.

[Dan N]

Good eye, Tim. Pin 6 was messed up. Here's another rip:

http://users.rio.com/senorris/junk/gonkschemaybeV2.gif

[Paul Perry (Frostwave)]

Charlie, maybe making the 100K resistor on pin 3 of U3/A variable would give you a frequency control.

[moosapotamus]

Thanks for the suggestion, Paul. I tried sticking another 100K across that one, but it didn't really do anything. After a little poking around, it seems the resistor that needs to be made variable (for a variable carrier frequency control) is the 33K that goes between pin 2 (U3a) and pin 7 (U3b). I tried replacing that 33k with a 100K pot and it works quite nicely, seems to cover at least three or four ocataves.

I might consider modding it so that the Heave (volume) pot controls the carrier frequency and just leave the overall output volume fixed. The Suck and Smear pots control the disto and ring mod output levels individually. So, the Heave pot seems kind of unnecessary, anyway.

Noticing something else in the schematic (thanks again, Dan!)...
Check out the section of circuitry that connects pin 1 to pins 8 and 10 of the 1496. This looks like the carrier signal is not going into the 1496 (carrier inputs) by itself. It's getting blended with the clean signal first. When you play through the pedal with the Suck and Gunk controls at zero, it doesn't sound quite like a true ring mod because some of the straight signal is still recognizable in the output. It doesn't sound like a pure ring mod sound.

So, what about breaking the connection at pin 8? Might that result in more pure ring mod sound? Could all those components between pin 1 and pin 8 be taken out, or bypassed? Or, what about disconnecting the carrier input at that point so that the clean signal goes into the carrier inputs and the signal inputs? Would this result in an octave-up sound, or maybe octave-up fuzz like the ringstinger does? What do you guys think?

~ Charlie

[Paul Perry (Frostwave)]

Thanks for finding the right freq resistor Charlie! how lame is a ring modulator without a freq control  :shock: as for putting a mix of original and oscillator in, the effect of the original signal going in the modulator input is to give frequency doubling (on single notes) and a more complex mix (like a chord thru a fuzz) on chords.

[moosapotamus]

how lame is a ring modulator without a freq control :shock:

totally... like a mustard without a ham.  :lol:

Hmmm... So then, do you think might it be interesting to try removing either the original signal or the carrier signal from the carrier inputs?

I know it would be fun to add an input for an external carrier (that I could plug my photo-theremin into :twisted: ).

Thing is, I'm not sure I really want to go and start cutting up traces on my Gonk. So, I may have to think about making one after all. :shock:

~ Charlie