I built a piggyback fuzz face using Induction's Javelina schematic.
Instead of using four 2n3904's I used one MPQ3904.
I did this for no other reason than the joy of trying to get a Germanium sound from an IC.
It sounds good but...
1. There is a whine when I turn the fuzz all the way up. Would boxing this completely cure this? (its currently in a cardboard box)? Will increasing the cap between base and collector on Q2 help this? Any wires that i should avoid having too close together? Anything else I should try?
2. The fuzz and drops off sharply when a single note rings, kind of like a noise gate. I'm not sure what to tinker with. I have played with the bias but the problem is there from 0 to 5k. This is the main problem as I can live with the fuzz at 90%
3. What should I do with pins 4 and 11 on the IC?
Also any other advice on why this idea was always doomed welcomed!