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The story of the Damocles starts when I picked up a Crate Blue Voodoo combo at a pawn shop about a year ago. The plan had always been to redo it into something good and maybe sell it.

The first step was to convert it to a Dumble sort of thing. I thought that having a hand wired Dumble circuit would make even a Crate something someone would want to buy. I first tried a D’Lite circuit but I didn’t really like it. That led to messing around with various Dumble circuits until I finally came to the conclusion that I’m not really into Dumbles. I’m more of a Trainwreck person. After that II tried various designs but didn’t really come up with anything I liked.

Finally I went with a 2 gain stage black face style channel with the tone stack in between. In addition to that there is a switch that can add two cascaded gain stages with a gain control and tone knob before the black face channel to add a bunch of gain. Where a Dumble amp adds two gain stages after the Fenderish channel, this one put two gain stages before. IMHO you can get way more gain that way. The switch also adds the master volume and alters the tone stack. I haven’t seen this topology used before but it should be. It makes for a very versatile amp.

Since this used to be a Dumble type amp I had some switches available so, of course, I have to come up with something. The Brit/American switch in the tone stack is actually pretty handy. It changes the tone stack from something close to a Blackface type to something close to a Marshall. I’ve found that in OD mode in the American setting you can turn down the mids and get close to that high gain, scooped mids Mesa sound or in Marshall mode you can get a pretty good high gain Marshall sound. I think that somewhat strange topology lends itself to being able to go Marshall or Mesa.

Another good sound is with the tone stack in American mode and switching in the OD circuit with the the OD set to low. With a strat you can get some really nice, just breaking up sounds. With this setting having the tone control on the overdrive comes in handy too.

Here is a comparison of the standard Fender black face tonestack and my tonestack in American mode with the mids dialed down a bit. The green line is the Fender and the red is this amp. Pretty close!

Here is a comparison of the Marshall Plexi tonestack and my tonestack in Brit mode. The green line is the Marshall and the red is this amp. Pretty close but less output because the Marshall uses a cathode follower.

This is a comparison of the Vox tonestack and my tonestack in Brit mode with the mids all the way down. The green line is the Vox and the red is this amp. Sorta close with the mid cut in the same place but the Vox has a wider mid cut and more low end.

The main thing this switch really does is move the center of the mid cut from about 450Hz for the Fender to about 750Hz for the British sound.

There is also a switch to control the bass. After playing it a little in the high gain mode I was hearing some strange artifacts in the low end. So I added a switch to reduce the cathode bypass cap on the last gain stage.

I’m also running EL34’s in it now. They have a great crunch and seem to emphasize the mids in this circuit.

Here is the schematic…

Here is a gut shot. It could be cleaner but not too bad considering how much experimenting went in to this one (and that is started out as a Crate Blue Voodoo).

onepixel Damocles_guts_v2

And, finally, here’s a clip. It starts clean and then switches in to overdrive mode.


  1. Hi, thanks for sharing your talented designs. All ive build so far is a 6G2 and a real beefed up
    AA1164. Regarding the Damocles, which OT did you use. Would a 6600 to 8 ohm OT trade
    for the 4000/8, and also get the wattage down a bit?
    What B+1 would best run this amp, around 420 maybe?

    • Hi, yeah I think a 6.6k OT would be fine. The OT I’m using is what was in the Crate Blue Voodoo. To be honest I’m not sure exactly what the secondary is. I’m guessing it’s about 4k. IIRC B+1 was about 440vdc . Good luck with the build. I think this amp is my favorite one I’ve built.

  2. Hi again, thanks for the last reply, are the russian 6N2Ps the way to go? I guessing you use them
    as they are cheaper and would be hard to hear the difference against a 12AX7.
    Do you use tube rectifiers at all? for that loose bluesy feel, or prefer rock/metal amps.
    Cheers Ant

    • Yeah, I use the 6n2p because of the cost and I can’t hear any difference in tone compared to 12ax7s.
      I usually go with SS rectifiers. For a looser feel I might use a sag resistor. I’m thinking of doing another Supro based amp soon and will likely use a tube rectifier in that.

  3. Hi, just seen the Park rock head sounds wicked, really like your work. As for Supro.. ive just gotta have one. Thunderbolt looks easy enough, not many components. The speaker will kill it for me, as im in NZ, so freight costs about 1.5 times more than speaker. If you build a supro will you use a
    15in speaker? I guess the 15 gives it the mojo? Cheers Ant

  4. This is a great design!
    I’m planning a smaller version, with two 6V6s (JJ) and a Heyboer TO22 OT with 6k6. What changes to the circuit would you recommend?

      • That sounds like it would work fine. The only change that comes to mind is to possibly experiment with the PI tail resistor. It’s 10k in the schematic but you could try increasing to 22k to reduce the drive a little for the 6V6s.
        Good luck with the build!

      • Sorry but I don’t have a layout. The layout I had was not that great as it was built on some D’Lite boards.
        I’ve since redone this amp into something along the lines of a Boogie Mark 1 or Lonestar. It’s a little simpler and works better on those boards.
        I’m going to revisit this design in the near future. I will probably do separate inputs rather than the switching. It is a cool design but i want to do a better implementation.

        • Where would you place a buffered effects loop in this amp? I think between the 47nF and the 100k before the Master Volume should work best? The loop is built around two LND150 and has pots for send and return.
          I think the switching makes this circuit really interesting. I’ll built it with a double footswitch, one for the channels, one for the effects loop.

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