Hi, my 1st post! Whoo...
You guys should check out
www.buildyourownclone.com
Kits to build Tubescreamer clones.
The JRC4558D chip that companies talk up, costs about 50 cents.
You can get 'better' sounding and quieter chips.
The forum there is also quite illuminating about some pedals.
Fulltone Fulldrive = TS9, with some extremely small changes.
I built a pedal called the ...UltraScreamer lol.
Its a tubescreamer, but with switchable diodes and a high pass filter freq select switch (think bass boost)
( I hope this picture works)
-Miles.