PARTICLE VINTAGE FUZZ
4
BUILD NOTES
Germanium transistor
The original Harmonic Percolator used 2N404A PNP germanium transistors for Q1. These are not
impossible to find on eBay and other vintage parts sellers, and NTE makes a new-production version
with the same part number. But as with most germanium transistors, the exact part number isn’t
important, so don’t spend too much time or money hunting down something that says 2N404A.
You’re looking for something that is low gain (30-50 hFE). The circuit is pretty tolerant of leakage, so
even something with a decent amount of leakage (150-300µA) will work fine.
Many people have used higher-gain transistors in this circuit and liked the result, so if you have a few
different types of germanium transistors, use a socket and experiment with them.
Silicon transistor
The original circuit used 2N3565 NPN silicon transistors for Q2. These are nearly identical to the
2N3904 (“real world” typical hFE range of 180 to 220) so there is absolutely nothing special about
this part. It’s recommended to just use a 2N3904 here, although if you want some extra cosmetic style
points, you can use a metal can silicon transistor such as the 2N2222.
“Albini” specs
The Percolator was perhaps most famously associated with producer & musician Steve Albini as one of
his “secret sauce” effect units. Curiously, his unit seemed to sound different from other Percolators, and
when it was dissected, it was found to have several different values than others that had been traced.
His is the only known unit to use these values.
Because of this, there are really two different versions of the Percolator, the “stock” version and the
“Albini” version. Many people prefer the Albini version, and so those values are provided as the default
configuration for the Particle in the parts list and schematic. However, the alternate values for the
stock version are provided as well. The sounds are very different to the point where they’re almost two
different pedals, so you may want to build both if you’re curious.
Q1 silkscreen
The initial release of the Particle (50 PCBs) had the silkscreen labels for Q1’s emitter and collector
reversed. The left pad is the emitter and the right pad is the collector. The image on page 1 shows how it
should be, labeled E-B-C, corrected in subsequent restocks. If your PCB is labeled C-B-E, the silkscreen
should be ignored.
