I have this problem, my homemade (solidstate) amp has recently started giving this farty distorted sound at higher volumes (quite nice effect for some songs ). Noticed that my pickups are very close to strings (p is 5mm from the string and j is 4mm from the string) that kinda sound only happens when i play harder. Im guessing that maybe its too much output... If that, how high should i set the p/j pickups??? It might be the speaker but i cant have it checked until next week.