Catalinbread - Karma Suture (germanium & silicon versions) [traced]
- aionios
- Solder Soldier
Information
An adaptation of the Harmonic Percolator with some added bells & whistles. The germanium version came out in 2014 and the all-silicon version followed in 2016. I hadn't seen details on either of them here so I traced both!
Germanium version:
Silicon version:
Full tracing journal (including photos of both versions):
https://aionfx.com/news/tracing-journal ... m-silicon/
PCB available here (supports either version):
https://aionfx.com/project/calliope-vintage-fuzz/
Germanium version:
Silicon version:
Full tracing journal (including photos of both versions):
https://aionfx.com/news/tracing-journal ... m-silicon/
PCB available here (supports either version):
https://aionfx.com/project/calliope-vintage-fuzz/
- Ben N
- Cap Cooler
Hey, Kevin, nice work. The demos of these things sound really killer. What I am not hearing in any demos is the wild octavy stuff that the original Harmonic Percolators were known for, although both versions are obviously very harmonic rich. Is that in there? Also, would it be possible to ditch the input control and just use the guitar volume for that? And how do both versions play with other pedals, fore and aft?
- aionios
- Solder Soldier
Information
Not that I heard in my build or listening to the originals. Both are more along the lines of the "Albini specs" version of the Percolator where they are lower gain and more controlled, more of a textured drive than a fuzz.
Definitely possible, but this input volume is actually the gain control from the original Percolator, so you'd be straying even further from vintage. For fuzzes that react well to guitar volume, I typically prefer including the input volume on-board rather than relying on the guitar. This way you always have the option to turn the control all the way up and just use guitar volume if you want, but you're not stuck without a gain control if you put the pedal someplace else in the chain where guitar volume doesn't have as much of an impact, e.g. after a compressor.
Not sure on that one, but likely comparable to the original Percolator since the input & output impedance are the same.
- toneman
- Resistor Ronker
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Hmmm.
No path to gnd for Q1 &Q2 common emitters(?)
Definitely not a FF. Uses diodes for clipping.
No path to gnd for Q1 &Q2 common emitters(?)
Definitely not a FF. Uses diodes for clipping.

Tone-to-the-Bone
- CheapPedalCollector
- Resistor Ronker
I was also just noticing no path to ground on the Q1 and Q2, resistor missing?
- aionios
- Solder Soldier
Information
Yep, that's the Percolator... It's a tangle of a schematic that doesn't resemble anything else, and there are a few different ways people have drawn it, but it always looks confusing. Maybe this other schematic makes it clearer though -

