Biasing a Jimi Hendrix Fuzz Face

[zombiwoof]

I recently bought a blue Jimi Hendrix Fuzz Face, which has the BC-108 transistors.  I measured the voltage at Q2 and found it to be up around 6 volts or so.  I have more experience with germanium FF's, and know that the suggested voltage for germanium FF's at Q2 is in the 4.5-4.7 volt range for the best clean-up and sound.  Is this also true for silicon Fuzz Faces?.  I've been told that this model has small bias trimmers hidden on the bottom of the board (although I haven't pulled the board out to verify this), should I try adjusting the bias down a bit, or is this higher voltage common for silicon FF's?.  A guy on another board said that he has the same Fuzz Face, and it also measured a bit over 6 volts at Q2, so I'm guessing this is how the factory sets them.
Thanks,
Al

[rousejeremy]

The 4.5 thing isn't as important with Silicon trannies. Adjust it by ear, leave it where you like it then measure it.
IMHO the silicon fuzz sounds better when biased lower than 4.5. Especially when run into a dirty amp or a little bit of overdrive.

[joegagan]

i vaguely recall a lot of people like hotter bias in the Si versions.
also,this was jeorge tripps' baby, he took great care on the details. i trust it.

[LucifersTrip]

i found the higher gain silicon ones sound more mushy & compressed....and setting Q2C higher gets rid of some of that (if you don't want it). Though, I usually don't set mine higher than 5 - 5.5v

bottom line is it doesn't matter where it's set as long as you like it

I would actually breadboard it and see what you like...or find those trimmers

[zombiwoof]

i vaguely recall a lot of people like hotter bias in the Si versions.
also,this was jeorge tripps' baby, he took great care on the details. i trust it.

Joe,
I know Tripps had a hand in this FF, and it very nicely made (those Omeg pots are the smoothest I've ever experienced on a pedal, I wonder where you can get them?).  However, since I bought it second-hand (although in mint condition with box and papers), the previous owner could have messed with the bias on it.  I really just wanted to know if a silicon FF is supposed to bias to the same voltages as the germanium version.  I guess I'll pop the board off, and adjust the trimmer(s) to where I like the sound the best.  I've heard they are very tiny trimmers, and that they are covered with little paper stickers (probably to keep people who don't know what they're doing from messing with them).

One thing I noticed, even though Dunlop says it is made exactly to the original specs, they again used a .1uf output cap (as they have done on every Fuzz Face they've ever made), when the original value was really .01uf.  This would seemingly make it bassier (I replaced the .1uf with a .01uf on my old red Dunlop FF, and it got rid of the horrible muddiness that it had).  I've always wondered why Dunlop always uses a .1uf cap there, I know there is one schematic on the net that erroneously says .1uf for that cap, but maybe they just wanted to voice the pedals for a bassier sound.  Every board pic of original Fuzz Faces I've seen shows a .01uf cap there, and most schematics show .01uf also.  Funny thing, though, in the case of this Jimi FF, I've only tried it out once for a bit through a Princeton Reverb, and it didn't seem to have the overly-bassy sound the red Dunlop FF's have.  Have yet to try it out through one of my Marshalls, but I'm going to do that next.

Thanks for the help everyone,
Al

[joegagan]

omegs have some heavy grease in them, they give a nice hefty feel, is that what you are referring to?

upon ken fischer's advice ( via a paul crowther recommendation), i switched to omegs in 02 after a disaster with weber vst's chinese CTS copies. they are hard to buy in this country, there was a 1000 pot minimum with the US distributor, and a bit of a lag time.

i still have hundreds, let me know what you need, happy to send some over. i have 22k linear, 100k log, 220k log and 100k log dual gang.

also, i found a site in europe that stocked alot of omegs. be right back with a link.

i liked your note about the .01 out cap on the fuzzface RIs

[joegagan]

this is the place that appears to stock  a nice variety of omeg values. now that the euro is collapsing, should be a good bargain for us.

http://www.tme.eu/en/katalog/#id_category%3D100018%26page%3D3%252C20

[joegagan]

i think tripps probably chose omegs for an authentic look inside. cool touch.