"222222" Darlington Harmonic Percolator

222222 is a distortion/fuzz pedal influenced by the classic NPN/PNP transistor pairing from a push-pull amplifier known colloquially as the Harmonic Percolator. The 222222 implements silicon and germanium Darlington Pairs as a sort of “Matryoshka principle” or Russian Doll style stacking of transistor amplification stages, or pairs within pairs! A Darlington Pair is a widely used transistor configuration that stacks two transistors to function as one. This configuration expands the useful potential of previously unused germanium transistors but also introduces more noise and leakage into the circuit. These conditions when paired (nice!) with the correct components produce a desirable auditory result :)

This is a simple pedal that remains useful and good sounding on most settings. Great volume knob and dynamic response from your guitar, with a very satisfying and warm "crunch" that veers away from the buzzy/synth sounds of traditional fuzztones, ie it sounds interactive with your guitar/amp and less like its being "filtered through" something. Basically you could put it in front of your tube amp with the knobs set to 3 o'clockish and never touch it again :)

Besides guitar it also sounds amazing on certain electronic audio sources such as modular synthesizers, drum machines, test equipment, etc. Because of the way germanium clips it behaves somewhat like a compressor/limiter with lots of strange dynamics, sustain and subtle fuzziness that is very useful processing percussive or other momentary sounds.

History

A Darlington Pair is a transistor configuration invented by an electrical engineer named Sidney Darlington in the early 1950s. It consists of stacking two bipolar junction transistors in which the emitter feeds into the base of another.  At the time it was a very useful way to increase a transistors current gain as the early devices had low specs and this greatly aided the development of sensing and switching circuits.  Like many early electrical engineering endeavours in North America it was undertaken at Bell Laboratories in the late 1940s through the 1960s.  Unfortunately it was most likely conceived as some type of utility for the military/industrial/capitalist complex as most engineers at the time were contracted either directly or indirectly by the massive influx of military spending during/post world war 2.  Sidney Darlington went on to produce bombing and rocket guidance systems utilizing new developments in radio encoding and modulation. 

This is a somewhat common methodology in many fields of electrical engineering including the design of guitar pedals.  It was initially used in various fuzz pedals as a way to try and use some of the old American transistor stock that had low hfe readings as the manufacturing process at the time left a lot of unusable product (for fuzz pedal purposes).  Recently I have been experimenting with this methodology for using low hfe 1980s Russian transistors.  Its a fun process thats usually not too successful, but every now and then you come across something worthwhile. Interestingly many of the problems that can arise from darlington pairs are often not present in these designs as Russian manufacturing continued producing germanium transistors well into the 80s and fine tuned the process, producing stock with very accurate and stable specifications.  

Strangely this specific run of pedals will not exist for too much longer as the current war in Ukraine and subsequent trade embargo on Russia has made acquiring affordable lots of germanium transistors almost impossible.  There will probably be another edition of 10-20 in a few months and then it will have to be redesigned for some other available part.  

Guitar Demo

"Synth" Demo