Aleph Null
Well-known member
I was inspired by the recent work of @DGWVI and @PedalBuilder with this circuit to devise my own deluxe take on the Harmonic Percolator. I wanted to cover everything from Albini type tones to the more velcro-ripping sounds of the consensus schematic. I also added an octave up for good measure.
Water slide decal on bare aluminum for the graphics. I wanted the metallic look of a Moka Pot.
I used my standard I/O and bypass layout.
A mosfet boost feeds the fuzz section to allow for more saturation. This is especially important as I decided to leave out clipping diodes. They just seemed to mask the character of the fuzz. The Lows control is pre-fuzz. From fully clockwise to noon, it tightens up the fuzz response. Below noon it noticeably attenuates low-end content. The Gain control is just a volume control for the boost output, which feeds the Harmonic Percolator section. I arrived at the values here after much experimentation, trying to get as much tonal variation as possible. The Highs control uses negative feedback to attenuate treble in the Q2 gain stage. Placing it here effectively cuts high-end content without masking the character of the fuzz. Clang sets the bias of Q3 (which in turn effects the bias of Q2). This goes from smooth saturation when counterclockwise (think Albini values), up through the spitty ripping-velcro type sounds the percolator is known for, and into farty misbiased octave down sounds as you move clockwise. Lastly, Octave blends in a separate octave up circuit, which is based on Tim Escobedo's Push Me Pull You, and is optimized to compliment the fuzz. As this sub-circuit comes after the boost and percolator sections, it is sensitive to the other controls.
I'm pleased wth this design. It gets all the sounds I'd want from a Harmonic Percolator while remaining farily ugly proof (for a fuzz).
Here's a demo:
As always, I have extra PCBs. If anyone is interested in building one, DM me.
Water slide decal on bare aluminum for the graphics. I wanted the metallic look of a Moka Pot.
I used my standard I/O and bypass layout.
A mosfet boost feeds the fuzz section to allow for more saturation. This is especially important as I decided to leave out clipping diodes. They just seemed to mask the character of the fuzz. The Lows control is pre-fuzz. From fully clockwise to noon, it tightens up the fuzz response. Below noon it noticeably attenuates low-end content. The Gain control is just a volume control for the boost output, which feeds the Harmonic Percolator section. I arrived at the values here after much experimentation, trying to get as much tonal variation as possible. The Highs control uses negative feedback to attenuate treble in the Q2 gain stage. Placing it here effectively cuts high-end content without masking the character of the fuzz. Clang sets the bias of Q3 (which in turn effects the bias of Q2). This goes from smooth saturation when counterclockwise (think Albini values), up through the spitty ripping-velcro type sounds the percolator is known for, and into farty misbiased octave down sounds as you move clockwise. Lastly, Octave blends in a separate octave up circuit, which is based on Tim Escobedo's Push Me Pull You, and is optimized to compliment the fuzz. As this sub-circuit comes after the boost and percolator sections, it is sensitive to the other controls.
I'm pleased wth this design. It gets all the sounds I'd want from a Harmonic Percolator while remaining farily ugly proof (for a fuzz).
Here's a demo:
As always, I have extra PCBs. If anyone is interested in building one, DM me.
