[2627] Increase Fuzz Face Output

Date: October 16th, 2019 | Comments : [3] | Categories: DIY.

This is the basic schematic of a PNP germanium fuzz face. Some players find that the output volume is too low, but there is a simple mod to fix it.

The R3 and R4 resistors are a voltage divider that is reducing the signal level going to the output. The sum of their values is also contributing to the operating bias for Q2, which can be measured as the voltage on the collector of the transistor. A simple way to increase the output volume is to exchange the values of R3 and R4 as shown in the schematic below. The bias on Q2 stays the same since the same two resistors are being used and there will be little or no change in the tone produced by the fuzz – it is just louder!

The same trick works for silicon fuzz face pedals as well, and NPN or PNP versions, though the values of the two collector resistors of Q2 may be different.

 

3 Responses to “Increase Fuzz Face Output”

[786994] Constantin Says: 6:46 am, November 7th, 2019

Brilliant. Like everything else you’ve taught us, Jack.


[787112] Jesse Yasaitis Says: 10:06 pm, December 5th, 2019

I bread boarded a fuzz face once, successfully. A few other times not so much. But, I digress, I found that the output was greater if I moved the C2 connection from its current voltage divider position, to the Collector of Q2 after R4.


[787165] Fran├žois Says: 8:11 pm, January 1st, 2020

I replaced R4 with a trimmer and increaced R3 to 3.3k for my Si fuzz face (low gain transistors, about 100-150 each), and it tends to oscillate (more like a high pitched squeel) when you max the volume, I tried several things, replacing the volume pot with a resistor and smaller pot in series, without success…


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