The XinSound Fuzz FD-20 is a Big Muff V2 Ram's Head guitar pedal clone.
It's schematic is next to the Electro Harmonix Big-Muff Pi 1975-15-10 original circuit.
As usually, I would like to experment on this pedal, doing some mods.
On the first and second gain stage of the original circuit, XinSound puts two soldered bridge to select which feedback loop diode and capacitors to use, a simple mod can be just split those bridge so try different sounds, it's the JP6 and JP7 bridge, you can see on the original board below.
The original electrolytics capacitors installed by XinSound where changed with Nichicon brand.
XinSound uses electrolytics capacitors on the clipping stage, but i prefer ceramic ones.
Also, all the four XinSound C1815 transistors where changed with classics 2N5088.
Below my modded board.
A Boost section it is added. The boost section produce an extremly clipped sound on bass.
One again many thanks to my friend Matteo for cutting me vinyl sticks for this pedal.
Found below the XinSound original schematic, as i've traced out, hope it does not contains errors.
And the modded one:
- read risk disclaimer
- excuse my bad english