Friday, 27 October 2017

Rozz Dead Heat

Here is an 18V Big Muff version from the 70s.
Original FSB thread and schematic available here.


  1. Maybe a good idea to put pin 5 of the 7660s to ground?

    1. for what? pin 5 is negative voltage

  2. Verified! Nice Muff variation. Used 5089s. Thanks Alex.

  3. Thanks for the post. I've built this and after a bit of faffing around (failed pot) it's working but with a terrible hum. I've tried it with some pulled bc547 and some brand new s9013 but the hum is still there. Reflowed everything. Only thing that's different from the layout is that I have used a 10nf instead of 8n2 and 120R instead of 150R on the emitters of Q2 & Q3. I can't see how these would cause hum (but may have other impacts). Voltages are a little higher than indicated on the fsb circuit diagram (psu puts out around 11v). Thanks for any advice.

  4. I guess you should try to change your power supply.

  5. Something I didn't mention was that I used 1n4007 in the doubler section. I did read somewhere that they would be suitable subs in some cases. On further reading it seems they may not be (but it doesn't say why, other than they gave faster recovery) . I'll try to find some schottky and see if that makes a difference.

    Would changing the psu (which works fine with other pedals) be necessary? We are aiming for higher voltage by having a doubler. Why not add a few more volts to the party?

  6. Hi Alex. I got my hands on another psu and I now see why you suggested changing it. Made a big difference to the amount of noise. Many thanks - now to experiment with other transistors. Cheers.