BMP with Germanium Transistors

Gila_Crisis · October 23, 2006, 04:59:08 PM

hi i found some ac188 germanium transistors, and i tought, why not put the in a Big Muff in place of the normal 2n5088/BC549???
do you think this would work?

i allready got i big muff a friend built for me, but it didn't work since it was built, so i thought to bring it back to life! it was made with the tonapad pcb if i'm not wrong. i only must check what is wrong, and maybe change 2 or 3 things.

Dragonfly · October 23, 2006, 05:04:31 PM

The main issue you'll probably need to address is biasing...its most likely that the AC188's will be out of bias if you just "pop them in there"....also, AC188's are PNP, so you'll have to change electrolytics around, etc....

IIRC, Frantones "The Sweet" is a germanium fuzz based on the Big Muff...i may be wrong though...

AC

tcobretti · October 23, 2006, 05:08:21 PM

If they are PNP Ge transistors you'll have to flip the pos/neg and the direction of all electrolytic caps. I suspect some side effects will be less overall gain, and more noise. However, it may still sound great. I personally would get the circuit working using some cheap low gain Si transistors, just so you don't put your Ge trannies at risk. If it sounds like total crap with low gain Si transistors, it won't sound better with Ge.

Dragonfly · October 23, 2006, 05:12:00 PM

i forget where it is, but somewhere around there's a "germanium pnp version" schematic for a muff...i'll look for it....

Dragonfly · October 23, 2006, 05:15:48 PM

this thread has a schemo for a pnp muff....

http://www.diystompboxes.com/smfforum/index.php?topic=34437.0

Dragonfly · October 23, 2006, 05:16:57 PM

...more muff info...

http://www.singlecoil.com/docs/vintage_muff.pdf

Gila_Crisis · October 23, 2006, 05:40:11 PM

i was thinking to change some components for the triangle version, the only problem is that there are 3 or 4 version of the triangle

but i think i'll follow the one found on tonepad.

any suggestions about that? which triangle do you think is "better"?

petemoore · October 23, 2006, 06:00:06 PM

which triangle do you think is "better"?,,,mine
according to Bill, all muffs are the same, it's whats around the Muff that makes it appear different from other muffs, this applies to the circuit as well IMO.
Best is what sounds better to you.
lower noise may not be a deal / you might like a noisy Muff, high gain and all...I haven't had one I liked that was quiet anyway, that's what I think the footswitch is for...
Ge muff probably takes more diddling with than an Si muff.
I'm using an NPN Ge on Q2 and have jumpered or lessened the R values to ground...some of the early transistor emitters...maybe upping the collector resistors to 12k from 10k...helps [I've read]...
A good muff has alot of gain...plenty of clipping...I just got it to where I turn the gain down most of the time...to about 8.5 or 9...and tweeked a bit on the Tone Control...lotsa muff mods out there...lifting the TC altogether, different diodes for clipping, but I find the circuit fascinating enough the way I have it set up, if I want even more I enable a booster or comp in front of it..after all I just use it as a monstrous distorter.

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BMP with Germanium Transistors