Edit 2: See my second post below for info on my improved design and layout. Schematic and circuit board images to follow.
I've got a problem with my fuzz. I designed a circuit similar to the Axis Face Germanium from several resources online, mainly based on RM's Jimi mods, Fulltone's 69 and the mods I'd previously made to my own late 60s Arbiter, and I wired it without the pulldown resistor, favoring the grounded input style instead, but when I switch the effect on, I get no guitar sound. I can hear the tiny hiss of the fuzz working, and all the knobs seem to do their jobs, but the guitar signal is not getting into the circuit. I've rewired it several times to no avail. Any ideas? Is the "Bias" or "smooth" control (I called mine the "pre" or "chutzpah") killing the input signal by shorting it to ground, since the pulldown resistor is absent from the circuit? My nets match those of the AF germanium almost exactly (how many ways are there to make a FF, really?), but I'm at a loss at this point. Help!
Edit: Never mind! Problem solved! With the input grounded and no drop down resistor, there is no need to have the "input/bias1" connections to the board. Just connect the switch to the 1st lug of the bias pot, then from the 2nd lug to "bias2" on the board.
I have completed my pedal, revised my circuit board and layout, and tried several different values for some of the components. The pedal sounds GREAT! It is still similar to the AFGe, but not exactly the same.
My layout more closely resembles the original Arbiter FF than the Axis Face, and I have made the board very flexible for several different versions, from a straight up Fuzz Face clone, to my final design, which is more akin to the '69 and Axis Face.
Use traditional radial or mini axial caps, and either a resistor or internal trim pot on the Q2 collector. Reverse polarity protection and filtering are optional (though I highly recommend them) as is the 'Britface' method for temperature stabilization (also highly recommended).
I believe this layout would be useful to anyone who is a 'tweaker,' always changing components and values in search of different tones, as well as a prototype board for either silicon or germanium fuzzes, as the Britface section can be ommitted for a silicon version. While the board does use slightly more space than the mini AF board, it is smaller than the traditional FF, and fits in a 1590B just fine.
If anyone would like me to post the circuit board and layout, let me know and I will upload them to the forum or email them to you.
