Wednesday, 2 March 2016
Electro Harmonix '75 Unknown Muff
Here's a layout for a big muff from a schematic from October 15, 1975. It's known as the mystery muff. Should be a nice addition to any muff collection.
The only deviation from the schematic is that I added the mids switch, I changed the 1uF caps to polys instead of electrolytics, and added a polarity protection diode. The transistors are unknown so I looked at the schematic for muffs of a similar vintage and they used BC239C's, but you can and may use more common Si transistors like 2N5088, 2N5089, etc. The diodes are also unmarked, as they were unknown from this vintage so I marked them as the common 1N914/1N4148's, but you can try other Si diodes.