Fuzz boxes

I designed the signal path for the Ryder amps.

The Ryder amp had a path that used a tracking diode clipper followed by a diferentiator. They called it "bell tone", not fuzz. It had a "long sustain", whatever that means.

As a long-time guitarist my impression is that guitarists tend to be a pretty conservative bunch, and often the reason for something being considered "the best" tends to be because that's the way the classic pedals were and those were the products that the great names of history used.

Certain signal paths and devices are sacred, like communion wafers.

As a long-time guitarist my impression is that guitarists tend to be a pretty conservative bunch, and often the reason for something being considered "the best" tends to be because that's the way the classic pedals were and those were the products that the great names of history used.

Certain signal paths and devices are sacred, like communion wafers.

I suspect it's a combination of several factors. What follows is speculation, not gospel :-)

As others have suggested: history and tradition. Musicians in the early solid-state era found germanium-based circuits which produced a pleasing sound, the sound became popular, and other musicians who wish to adopt that sound find it easiest to simply reproduce the original circuits.

Voltage compatibility. Germanium has a lower transition voltage than silicon (roughly 200 millivolts vs roughly 650). It's possible (I speculate) that some early fuzz circuits were being used with instrument pickups with low output voltages and no preamps... and they wouldn't fuzz or clip if they had been built with silicon transistors because the input signal levels were too low for that. (I once built a passive fuzz-box for a classmate, using a simple anti-parallel diode pair. Didn't work worth a darned.)

Switch-on behavior. I looked at some measurements that had been taken of different varieties of germanium diode, and there's quite a variation in the current-vs.voltage curves. Some "switch on" rather more gradually than others... while today's silicon-based diodes tend to switch on quite rapidly (a near-"ideal" curve). I don't know how much of the variation in the behavior of the germanium devices is due to variations in the diode structure itself, and how much is due to a relatively high series resistance. In either case, in many circuits, a slow-to-turn-on germanium device would tend to clip the signal more gradually as the signal level rises, and thus would tend to have a different balance of fundamental and odd-harmonic frequencies than a faster-switching device. This might give the musician more delicate control over the amount of clipping/fuzzing being applied, compared to a fast-switching diode/transistor which would clip quite abruptly when the threshold signal level was reached.

If I recall correctly, germanium diodes (and transistor junctions) are relatively "leaky" by modern standards, and both reverse and forward leakage might affect the sound that they impress on a signal going through them, I suppose. It'd probably depend on the circuit in which they're used.

This doesn't answer your question, but might offer a vague example of the differences in the sound (distortion) produced by Ge vs Si transistors:

"Arbiter Fuzz Face"

My guess(tm) is "harsh and aggressive clipping" translates into more high order harmonics for Si. On an oscilloscope, that would look like a rounding of the sharp corners of any fast risetime waveforms.

A few decades ago (about 1967?), I would try to repair almost anything for anyone who walked (or crawled) into the shop. I don't recall the maker or model of the fuzz pedal but it looked something like this:

As for using an op amp and diode clipper, it's possible. However, my guess(tm) is that the typical buyer is trying to imitate the sounds produced by the name brand players. It's quite easy to produce a linear and low distortion device using modern components. Reproducing the strange noises and non-optimal sounds belched by a device full of sub-optimal components, is actually quite difficult. For example, how does one design something that has the proper "presence" and "ambience"?

Note that some of the effects projects at:

Oops. That should be:

My guess(tm) is "harsh and aggressive clipping" translates into more high order harmonics for Si. On an oscilloscope, that would look like a sharpening of the corners of any fast risetime waveforms. ~~~~~~~~~~

Low damping, so the tone dies away slowly.

Joe G

yeh, things like new old stock silk wound wire done by naked virgins under moonlight in the amazon jungle delivered wrapped in tweed and then twisted in a certain way named after some guy that did it 50 years ago, is the way to really get the right "tone"