This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Friday, November 1, 2019

Fulltone Mas Malo

For Fuzz Friday, here's Fulltone's take on the Big Muff. The main differences over a regular BMP is the input and output stages. The input stage has it's own gain control and the output stage is a JFET-based gain circuit. Also the volume control has been moved immediately after the tone stack, with the output stage after the volume pot. Schematic for reference.


  1. Verified.

    I had no BC184L's so I used some SC1815's with hFE readings around 350. I'm not sure how much the choice of transistor affects the sound, though Kitrae's Big Muff Page says it shouldn't matter too much.

    My build sounds tighter and less fuzzy than a typical Muff, and can do overdrive like in the demo by lowering the Hot and Drive knobs. Turning these knobs up brings gets closer to the traditional Muff sound, though the Hot knob can cause some hum when fully clockwise. I tried increasing the input capacitor to 100nF, which made the effect sound slightly looser, but still more on the OD/distortion side.

  2. What potentiometers are used in Fulltone Mas Malo i have checked the pedalpcb docs but there seems to be an errors with the pots types a,b,W so please help me.