RO Dream-Rig Circuit 3.3 PUBLIC

Tubulation Distortion Circuit for Dream-Rig Project

"Tubulation" distortion circuit for the Dream-Rig Project. Suggestion: Build two of these circuits; one for Channel 3 and one for Channel 4 of the 1-of-4 Exclusive-Selector (at Inputs or Outputs) but with different settings. Example: Set Channel 3 with less distortion and less gain (for crunch rhythm or moderately distorted solos) but Channel 4 for maximum gain and distortion (for extreme soloing). Controls Include: Input Gain, Clean Bass, Clean Mid, Clean Treble, Clean Volume, Distortion 1 Drive, Distortion 2 Drive, Distortion 2 Gain, Distortion 2 Tone, Distortion Attenuation, and Output Gain. Clean and distorted signals are mixed in the Output Stage. Alternative: Keep the MOSFETs in one of these circuits but replace the MOSFETs in the other with 12AX7A preamp tubes. Instructions are given at bottom of the diagram. Note: Op-amps were chosen to provide JFET distortion when overdriven, but if cleaner op-amp operation is desired, replace IC1 and/or IC2 with an OPA2134PA. Observe that the battery can be replaced by a regulated +12VDC supply. Experimental circuitry. Breadboard test before committing to a soldered build.