This listing is for Russian military grade NOS (new old stock), MP20B PNP Germanium audio transistor suitable for use in building Rangemaster, Tonebender or Fuzz Face style guitar fuzz circuits or as a replacement transistor in the preamplifier stages of many 1960's transistor radios, record players and amplifiers. It is similar to the AC125, AC126 and AC128 (when used within 150mW dissipation, 30V max).

These transistors have been hand tested and measured with an Hfe (gain) between ~90 and ~99 with a leakage ~ ≤ 132µA (not mA) 

This transistor has a following within the pedal-building community for classic fuzzbox circuits, where many feel that it produces the same 1960's Fuzz Face sound. These are the higher gain MP20B transistors, NOT to be confused with the lower gain MP20 or MP20A often found advertised online... those transistors won’t deliver the same results in a standard fuzz face circuit!

Manufactured for the Soviet military and with a guaranteed high specification, box marked with the OTK3 approval stamp,  data gives an Hfe (gain) figure of 50 - 150. These are individually hand-measured for Hfe (gain) and leakage.  Note that the pinout is (viewed from the underside with the center pin at the bottom) Collector, Base, Emitter from left to right; note that the Base lead is connected to the case of the transistor! Transistor(s) ordered will be sent randomly from within the group.

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MP20B / МП20Б Germanium Transistor USSR

Datecode: 1992

Military grade.

Datasheet parameters:

PNP

Pc Max: 150mW

Ucb Max: 50V 

Ic Max: 300mA 

2 MHz

Hfe for low signal (Ucb=5V, Ie=25ma, f=270Hz)  50-150

Each transistor is hand-tested for Hfe (gain) and leakage using Peak DCA-75 and GM-328 (results between the two testing meters is ~1%) at room temperature (~68° F) using tweezers (not fingers) to connect the transistors to the meters.

NOS, unused.