Blue Magic is a very low to medium grit, tube-like, overdrive pedal that is based on a MOSFET (BS170) pushing a JFET (J201) into distortion. Voltage at the JFET drain should be about 4.7, but tune by ear. [The 22k resistor] smooths out the sound, but at the cost of sounding less “open.” Thus, reduce [it] for a more open sound. Also, experiment with the coupling caps and the source bypass caps.
I've increased the power filter cap and added polarity protection. You can board mount pots using right angle PCB mount pots from the solder-side of the board.
Verified! I had to try it late night but sounds great. The tone pot really darkens the sound, I had to turn it full CW to hear a normal amount of presence. The mid switch is very subtle and works in lower gain settings with the stock values.
ReplyDeleteThanks for verifying!
DeleteUnable to get 530pF.
ReplyDeleteCould be 560pF or 470pF