Devi Ever's Torn's Peaker Questions

[rocinante]

Hey,

I'm building a friend of mine a kind of fuzz + tremolo project housed in one enclosure using the EAtremolo and Devi Ever's Torn's Peaker fuzz.  My question is about the fuzz circuit (http://www.deviever.com/fx/devi-ever-diy-schematics/) - the top left one.  I haven't yet boxed them and they are still separate circuits on breadboard atm.

Ive finished it and it works alright, but there seems to a few things to iron out..

Firstly i have replaced both 20n with 22n caps (because i didnt have any 20s) and the MPSA18s with 2n5088s (because i read they are similar enough to get the job done).  It is also running on 9v using a Trex Fuel tank.

Firstly - I get a horrendous oscillation (its roughly 5k) when i have the first pot open between the input and the 0.001uf cap.  Only when my tone pot is fully open on my mustang mind you. Both my amp and guitar are quite trebly, but this isn't a normal sound.  Would swapping that cap for a (higher/lower) one fix that??  I'm not really sure exactly what that pot is doing to the circuit. 

There also seems to be a lack of Pull down resistors and a radio frequency low pass on the circuit.  I'm still pretty new at this but would it be worth putting something like that in there - unless it is there and i am blind??

One last question.  She has oscillation points on the scematic - what would those be useful for/what do you do with that information?

Thanks very much in advance!

[rocinante]

Just a quick update:

I removed the 1n cap in question (between the first pot and base of mpsa18) and i got rid of the squealing oscillation.  But if i replace with any other cap less that ~20n i still get the 5k oscillation.

I'm kind of stuck on this - ive tried subbing out the input cap and tried a radio frequency low pass with no luck.

Any help would be much appreciated.

Thanks again
Steve

[rocinante]

UPDATE:

Thanks to help from Petey twofinger, i have subbed out the 2,2m resistors with 3.3m and that all but got rid of the oscillation.  I believe (from my layman's reading of the datasheets) that the 2n5088 has a max gain of 900, while the mpsa18 has a max gain of 1500. So that could account for the difference im guessing.  Thanks again man!