PNP Fuzz

Posted: February 24, 2014 in Effects
Tags: , , , ,


This began as a Fuzz Face that I was going to tweak.  I decided to place a buffer at the front and it changed the sound, so I started playing with component values.  Once I placed the treble control in the circuit, it made a subtle difference and I began replacing capacitor values until I was satisfied.

(Update 3/5/14)  I used the same buffer in this schematic while breadboarding another circuit.  It worked much better as a normal gain stage (coupling cap come from the collector instead of the emitter).  The whole idea is to use a buffer in front of a lower impedance stage, so it doesn’t load the guitar.  When I used a transistor in a low gain stage into a stage with an input impedance of only about 100k, it was probably loading the transistor circuit, but it sounded fine and didn’t load down any guitar I plugged in (high output and low output passives and an active).  One of these in front of The Sweet Peach Fuzz would be excellent.


  1. The cap from the wiper of the Fuzz control to the power rail controlled the girth of the fuzz control.  Changing it’s value didn’t have as much impact on the overall circuit as some of the other caps.  I tried 1u, 2u, and 100u along with the final value of 47u.  Each added depth to the fuzziness.  2u sounded pretty good and 100u was too much.
  2. The cap values will determine the voice of the fuzz.  Larger values up front distort more bass.  Larger values at the end allow more bass to come through.  If you want a “topp-y” distortion, lower the output cap.  If you want more bass frequencies to be distorted, increase the caps in the beginning.  I found that increasing the caps up front made the fuzz sound like a wet fart, but your mileage may vary.
  3. The 2.2M resistor control the gain.  Having such a large value is most likely introducing some resistor noise.  The trade off is having plenty of gain throughout the travel of the 10k Fuzz control.  It could be decreased, along with decreasing the resistors to ground above it, but I like it where it is.
  4. The Fuzz control is more like an Intensity control.  Rolling it back makes the fuzz sound more like a vintage fuzz.
  5. I tried including a more elaborate tone control (A James control to be exact), but it sucked all the signal right out.  The addition of another gain stage would enable a more elaborate tone control.
  6. The sound I’ve come up with is a cross between a modern high gain distortion and a fuzz.  Rolling the treble down tames the fuzz and it could be used for metal.  I think it sounds like a Dual Rectifier on this setting (I am using the clean channel of a Dual Rectifier for testing, so it may influence the sound I am getting, though the amp circuit is much different on clean).

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s