Where to start tweaking resistor values in the Fuzz Face?

[soggybag]

I just built up a Fuzz Face with some Ge transistors and I want to tweak the resistor values a bit. As it is things sound OK. But they might sound a little better if I tuned things up. There are several resistors and they all seem a little interactive. Where's the best place to start?

[LucifersTrip]

I just built up a Fuzz Face with some Ge transistors and I want to tweak the resistor values a bit. As it is things sound OK. But they might sound a little better if I tuned things up. There are several resistors and they all seem a little interactive. Where's the best place to start?

Good to show the schematic for reference...but the one on the 2nd tran's collector is always a good start

[soggybag]

Thanks for the reply. Noe that you mention it that seems like an obvious choice.

While we're on the subject, when it comes to biasing the first transistor, it seems to me that both 33K off the collector and the 100K from the base have a hand in setting the bias. What's a good approach here?

[darron]

read the bottom of geofex....

http://www.geofex.com/article_folders/fuzzface/fffram.htm

or better yet, all of it.


pretty much you can get a bit more gain out of it, which doesn't hurt...

it's a simple circuit, but you would replace every component i guess (:

[roseblood11]

The fulltone 69 is a good example for simple tweaks for a FF.
http://diy.musikding.de/images/stories/face69er/69erschalt.pdf

Replacing the 8k2 at Q2´s collector with a 10k trimmer and a 1k fixed resistor in series is the most important addition to the original circuit. If Q2 is misbiased, the pedal sounds like crap - that´s why maybe only 1 out of 10 original Arbiter Fuzz Faces sounded good.
The contour pot is also great and simple to do. Bias is an added pot in front of the input cap - interesting, but I never use it.
The most useful mod for me is a switchable input cap. The 2,2µF lets a lot of bass into the circuit, what makes the sound quite muddy. Switching to a 0,047µF brightens the sound. Wire both caps in series and put a switch across them, so that one or the other of the caps is shorted by the switch. This way, it won´t pop when you use the switch, because both caps stay connected all the time.

Note that the musikding-schematic has a 100nF output cap, which sounds too muddy for my ears. I´d stay with the 10nF, or maybe a bit more.