Friday, 25 January 2013

DOD FX50-B Overdrive Plus

Here's DOD's step up from FX50 :)

Just finished building this. The pot tapers are not mentioned in the schematic, so i went with the usual tapers from most designs. However. Volume needs to be linear and drive reverse log to get the circuit act like the original unit. Other thing was the 470R resistor on the bottom left. 470R gave me lots of oscillation when gain was cranked, so i swapped that to 4K7, which fixed the problem. I do believe that's an error in the schematic i did this from, but i can't be certain. Anyway - it works like a charm and is very nice OD indeed. Fat and smooth.


  1. I've got one of these, and was never keen on the sound, regardless of the different guitar tones I've liked through the years. I just has been accompanying me through 20-odd years, being ignored in the bottom of a box.

    1. You should feel pretty good about having it:
      That's $200 lying at the bottom of that box. Bet you didn't pay more than $50 for it :)

  2. i'm going to build this one next.

  3. built it yesterday and it actually sounds pretty good. it doesn't have all that much level unless you have the gain cranked up and it's actually below unity when the gain is at the minimum and the volume at max (running the pedal clean). I wanted it to have just a bit more output level so I added a Jfet booster to it at the output and IMO, the pedal is ALOT better now.

  4. hello guys!
    i've opened the original, and there is one more ic
    and 3 transistors.
    and an other one that says 751PN100A

    any ideas?mine seems a little bit older than the one in the that why?

    1. They'll almost certainly be the parts which were omitted for the bypass switching