Germanium vs. Silicon Transistors

One facet of the design process here at Keeley Electronics comes down to selecting not just the highest quality components for use in our pedals, but the right component for the sounds we’re trying to achieve. Sometimes it’s planned out from the start, other times it’s a process of experimentation, but either way it’s always towards the greater good of our products.

germaniumWith that in mind, you may have noticed that some of our pedals (Java Boost, Fuzz Head etc) use Germanium transistors to produce vintage inspired tones. Germanium is a chemical element with symbol Ge and atomic number 32, that’s used as a semiconductor in transistors and diodes, popping up in a few classic effects like the early period Arbiter Fuzz Face, the storied Dallas Rangemaster and the Maestro Fuzz-Tone.

“Subjectively the sound of Germanium offers a smoother, more-ear pleasing distortion. Whether that’s technically due to greater capacitances, lower bandwidth (Germanium can’t handle those higher frequencies that can sometimes lead to harshness) as well as lower gain, can sometimes lead to more gratifying sounds. There’s another phenomenon called Miller capacitance, which is the capacitance between the pins and the internal structure of transistors or tubes— which leads to smoothing and roundness, attributes that sound better to us guitar players.” – Robert Keeley

tesla-transistorGermanium parts had their heyday during the first decade of semiconductor electronics, before being widely replaced by ultra-high purity silicon parts. For a wide variety of uses, silicon offers superior performance and quality control, for less money. The music world is a different beast though, with very subjective tastes, and so germanium remains highly desirable for certain sounds, cropping up in everything from clones of ’60s pedals, to Chandler Limited’s line of germanium transistor based studio electronics.

Germanium is harder to come by than silicon, as it represents a small fraction of the semiconductor market today. Despite that, it still offers the best way to achieve certain, especially smooth distortion, fuzz, or overdrive characteristics. Germanium will sound a tad different than silicon in a given circuit, but it’s also worth pointing out that a great many excellent sounding pedals uses silicon components.

“It’s funny actually, the exact limitations that caused Germanium transistors to fall from favor in large scale electronics manufacturing, are the same attributes that make them sound so great in guitar pedals.” – Robert Keeley

An excellent illustration of the difference can be found in our Time Machine Boost pedal, with its separate Vintage and Modern channels. Classic germanium boost pedals inspired the Vintage channel, while the silicon JFET based Modern channel offers great transparency in contrast. So, if you just can’t decide between silicon and germanium, you may not need to; the Time Machine does both.

Here is a video that demonstrates the subtleties between Germanium and Silicon chips.