Low Voltage Organ Overdrive with 12AT7 (ECC81)

It was 2010 I guess, I have been using my JCM800 preamp for distorting my KORG CX-3 compact organ (famous Hammond C3 clone, Manfred Mann plays it, too). But the sound was not as crispy as I intended it to be.

Then one day I stumbled across this project :


The Peppershredder by D. Munzinger is a guitar distortion with two 12AT7 (ECC81) tubes that operates with an anode voltage of only 12V. Astonished by the possibility of such a thing I started playing with a Brimar 6060 tube that I had laying around (very close to a 12AT7). Heating as well as anode voltage was supplied by an old AT computer power supply.

Within half an hour I had a “one tube circuit” before me that could amplify (or at least buffer) the audio signal from my KORG CX-3 organ. And It got better: This crude tube preamp was easily overdriven by cranking up the volume knob on the organ.

I was amazed how good it sounded while it consists of yet so few parts. The rest of the evening/night I spent building the overdrive into a nice enclosure.

Find the schematics here: 12at7_overdrive.pdf

(there is a little blah blah in german along the schematic, nothing too important)

It is basically the first stage of the LoV Peppershredder with small modifications.

Here’s a little vid of the overdrive in action (sorry for the bad video quality though):


One response to “Low Voltage Organ Overdrive with 12AT7 (ECC81)

  1. Oh my god.
    That ia fantastic!
    I just found this and I’m floored…
    I have no electronix skills whatsoever…..
    Any chance in hell you’d build one for me? Happy to pay!!
    I play hammond but no leslie, and my boss emulator is the worst on OD…
    Seriously, would you could you for a fellow player dying with fake OD?
    Keith sturgeon

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