Mudbunny - Musket Fuzz?

[petesz]

Hi all,
Ive been trying to make my mudbunny into a (kind of) musket fuzz.
I hope its ok for me to post this schematic here, just to illustrate what ive done. Its from FSB.

Basically the bit in the blue shape i built on perf, and then i populated the mudbunny with the civil war parts list but left out R1, R2 and C1. From the 'out' of the perf i went into the C1 pad on the mudbunny.
I also used BC550B transistors, used 470pf caps instead of the 430pf indicated for the civil war specs, and i put the diodes on a switch with 1n914 in parallel, and mosfets (irf520) in parallel.
Now, if i turn the pre, focus, sustain or vol knobs up anywhere past about 12 i just get this feedback squealing noise. When i play it sounds awesome or if i turn them down enough to eliminate the squealing it sounds fantastic but im wondering why I'm getting this horrible feedback noise? Also with the diode switches on the 1n914 diodes the feedback gets a lot worse.
As far as i can tell its correct to the musket schematic.. Should i have R1, R2 and/or C1 on the mudbunny board?
Thanks
Pete

I'd better add: I had no 390R resistors, so i put two in parallel (580 and 820 i think?) to get about 330R for both R11 and R16.. could this be giving the circuit too much gain?
Also for the input to ground resistor on the perf board i had no 1M so i put two 2.2M in paralell to get 1.1M, but i think this would be ok.?

Ill also add that the mudbunny circuit works fine if i go straight into it without the perf in front..!

[stecykmi]

if the mudbunny works without the perf, i would check over your work on the perf. Check for solder bridges. It may be oscillating by itself.

You could also go through it with a probe and see where the oscillation starts...