Tonefiend Forum

Here I set up a FF with sockets for the transistors, input and output caps. I used Milmax in line headers. Cut two pieces with three pins for the transistors. I cut 4 more pieces and removed the plastic for the cap sockets.

Hard to see in this photo, the input cap plugs into the two sockets on the right. Center bottom there are two more for the output cap.

I figure I can test caps and transistors with this box, and solder the parts into the other boxes as a I make them.

I made one with stock values first. I noticed the output was low. It's a little over unity with volume maxed. I used 100K pot for volume on this one. I might have to switch back to 500K pot to bring the volume up a little more.

After some testing and scouring the old ampage forum, I have a few conclusions. The input and output caps are only two thirds of the story. There is another cap that effects the tone. This is the 20µf cap connected to the 1K pot off the emitter of Q2. Some explanation, the cap acts as a resistor to an AC signal. The resistance coming off the emitter of Q2 sets the gain of Q2. The larger this cap is the wider frequency range. When this cap is a large value the gain for all frequencies is high, when the value for this cap is smaller, lower frequencies do not see as much gain as higher frequencies.

From the amateur perspective, a 0.1µf cap more or less covers the frequencies produced by the guitar. We're talking the vibration of the strings on the frets. Overtones cover a larger range of frequencies. So really a 0.1µf value should get the standard range, while larger values get all of that other stuff.

Originally I had thought any large value here will get the full range. I often used 47µf. Which is fine, you could even go up to 100µf! These large values give those classic and wooly Fuzz Face tones. Smaller values in the 0.1µf range start to shave off the wooly and give a fuzz focused on a tighter range of frequencies. In many ways I see these three caps have a greater effect on the sound of the Fuzz Face than the gain of the Transistors.

More to come, I'm off work next week, the kid is in school, I'm planning to experiment and finish up a few Fuzz Faces.

I'm gonna build this in a couple of weeks 🙂
How to I leave the LED out, for longer battery life as per Joe's recommendation? I mean, how to I wire the switch and so on?