Fuzz Detective: The Plot Thickens!

Man, I’m glad I announced my intentions about this project! Thanks to your links and suggestions, the “Fuzz Detective” project has grown vastly more ambitious. I need a few more days to make my test recordings are assemble the results, but I believe this will be the most complete and “scientific” audio comparison of 1960s fuzz circuits yet attempted. I’m posting this update to share my current plans — and solicit last-minute suggestions for improving them. —Joe

Wanker's Dozen: twelve Germanium fuzz pedals compete on a level playing field.

Wanker’s dozen: twelve germanium fuzz pedals will finally compete on a level playing field.

I’ve been a busy little solder monkey! Dig my new pedals:

1. Maestro Fuzz Tone FZ-1 clone
2. Sola Tone Bender “Mk I” clone
3. Sola Tone Bender “Mk 1.5” clone (near-twins: Vox Distortion Booster, Italian Vox Tone Benders)
4. Dallas-Arbiter Fuzz Face clone (very similar to Tone Bender Mk 1.5)
5. Hornby-Skewes Zonk Machine clone (near-twin: Tone Bender Mk 1)
6. Sola Tone Bender “Mk II” clone (near-twin: Marshall Supafuzz)
7. Orpheum Fuzz clone
8. WEM Pep Box Rush clone
9. Mosrite Fuzzrite clone (germanium version)
10. Selmer Buzz-Tone clone
11. Sola Tone Bender Mk III (“3-knob”) clone
12. Baldwin-Burns Buzzaround clone

About the Fuzz Detective project:

I’m attempting to create a comprehensive comparative sound library of germanium-transistor fuzz pedal circuits.

There’s no shortage of audio clips and demo videos featuring the great stompboxes of the ’60s and their modern clones. Yet it’s difficult to make qualitative comparisons between circuits because there are so many other variables at play. Who performed the examples? Using what gear? Were the examples recorded in a pro studio or on a mobile phone? Are the pedals ’60s originals or modern clones? What’s the condition of the transistors? And so on.

This isn’t about, say, deciding who makes the best Fuzz Face clone. The focus is the circuits themselves. The Fuzz Detective project aims to “level the playing field” by removing as many variables as possible.

I’ve built twelve new clones from scratch based on their widely available schematics. These represent most of the fuzz circuits produced between 1963 and 1968, at which point silicon transistors rapidly replaced germanium. The list includes relatively familiar circuits, such as the Fuzz Face and Tone Bender Mk II, alongside more obscure ones, such as the WEM Pep Box and Selmer Buzz-Tone.

Here are some ways I plan to “level the playing field”:

  • I’ll use the same musical examples for each pedal and aim for consistent performances.
  • I’ll use the same guitars, amps, cables, mic, and recording chain.
  • All 12 pedals use new-production AC-128 transistors from the same vendor. This is the most widely available germanium transistor. I’ve measured each transistor for appropriate hFE (gain).
  • All pedals use old-school positive-ground power.
  • All pedals are powered by fresh 9v batteries (except the two 3v circuits, which are powered by fresh AA batteries).
  • Aside from their germanium transistors, all pedals use modern parts: carbon film resistors, mylar box-style capacitors, true-bypass switching, etc.

Regarding parts selection: I believe that placing stock in rare, “mojo” parts is bunk, usually perpetrated by people with large quantities of rare, “mojo” parts to sell. Germanium has a unique sound, clearly distinguishable from (though not necessarily superior to) silicon. But there’s surprisingly little sonic difference between any two properly functioning germanium transistors of equal hFE (the unit used to measure transistor gain). Meanwhile, there are no meaningful differences between the sound of vintage and modern passive components (capacitors and resistors). (See my Germanium Mystique post for more details.)

That’s the plan so far. My questions for you guys:

  • Am I missing any important ’60s fuzz circuits? (I’ve deliberately omitted ’60s fuzz pedals that exclusively used silicon transistors. No Electro-Harmonix Big Muff, Jordan Bosstone, Shin-Ei Companion, Univox Super Fuzz, etc.)
  • Can you suggest any improvements to my proposed methodology?
  • Anything else worth mentioning?

Thanks again for your help! And by all means, share this info with any fuzz-crazed friends. The more input here, the better!

BTW, these pedals are sounding fantastic! I couldn’t be happier with the new-production germanium transistors. And I can already promise many interesting surprises and fun discoveries.

21 comments to Fuzz Detective: The Plot Thickens!

  • Bear

    Looks like a good game plan so far. I would emphasize testing with two types of amp settings, one clean(or cleanish) and one already into break up. Some fuzzes like a blank slate, others need to work synergy with the amp to sound their best.

    Are you using Mammoth for your germs? What kind of variability/sorting needs are you running into?

  • joe

    Hi Bear! I bought the transistors elsewhere. (I’m sworn to secrecy about the source.) But while I’ve heard isolated complaints about Mammoth transistors, I’ve had universally good luck with them. (Part of the issue may be that various new-production transistors aren’t always oriented the same way. I often find myself rotating the transistors 180° while testing.)

    • Oinkus

      Only had a few of them but every one I have gotten from Mammoth were 100% (cheer for random luck!) . Now to build the Fiendmaster !

  • NotSoFast

    Wow – great blog. This is fantastic. My wife wonders why I keep accidentally calling her flowers Germaniums…

  • I’m on the edge of my seat.

  • Hi Joe,

    more fuel for your crusade against silicon.

    Germanium transistors were known for a few dreadful problems like leakage and temperature drift, which is why everybody tried to avoid them in the advent of more stable silicon. It is their sonic qualities that keeps them alive.

    However, a few geniuses have found that a great lot of this sound could be attributed to their low gain and they consequently made a low gain transistor silicon version.

    I have built it and it sounds by no mean inferior to a germanium version, letting alone the fact that most of tone comes from intonation.
    It behaves exactly like a ge fuzz. May I recommend you sling one together and give it a shot. You may even be able to use the same PCB for it.

    It is based on the Fuzz Central “Axis Face Silicon” and I have made some (what I call) worthwile improvements which you can behold on my site dedicated to stompbox weirdos: https://aquataur.at.tf/

    While you are lingering there, you may also be able to spot another yet unseen retro gizmo.:smirk:

    BTW this is a good chance to utter how much I enjoy your videos.

    have fun,


    • joe

      Thanks for the kind words, Helmut. I enjoyed checking out your site! Lots of cool ideas and projects!

      Oh, for me it’s more of a pro-germanium crusade than an anti-silicon one. I used silicon fuzzes and distortion pedals all the time. I simply tend to think that there are many players out there who could do a lot with the unique dynamic and harmonic properties of of a well-tuned germanium transistor pedal. But I’ve had great success with some silicon-based, two-transistor pedals. I have a big box of (relatively) low-gain silicon transistors, and use them often. I’ve never made an Axis Face, though — but I definitely will! A silicon transistor with an hFE measurement of, say, 100, works better in circuits like these than, say, a commonly used 2n5088 with an hFE of 400. But the low-gain Si transistor still sound real different from a Ge one.

      • Great you liked the flashback look. I am a bit lazy with the updates. There have been several projects in the meantime that are not documented yet.

        The reason I landed with the Axis Face was that I could not get any Ge trannies working – just farting noises and sputter of misbias.
        The Axis face does mostly what I wanted. It is however true that in the right hands a gefuzz works wonders. There is some mild and creamy texture to it. But as you showed elsewhere, take away some of the bass and the fuzzyness goes away for some really usable overdrive tones. I found this to work on many of the 60ies type distortion boxes. No miracle – most of them are in some way based on a fuzz face and it so happens, you have them neatly rounded up on your coffee table. :smirk:

        Apart from the chosen route (Si/Ge) is valid what I wrote in my poker-face article on the input/output mismatch of the fuzz face. Some people seem to like that but fixing its funny behaviour (volume pot of the guitar behaves differently, fuzz face squeals on wrong subsequent effect…) is not detrimental to tone and makes its usage more predictable and independent of what comes before or after. A

        Your guitar looks into the face and sees … nothing :smirk: – a pokerface! A vintage effect with modern attitude.

        have fun,


  • jeremy

    I wonder how they compare to a Project WEM? 😉

  • joe

    Hey, you’re getting the first WEM fuzz, at least!

  • Ronnie Ocherry

    Why not recording the guitar on a looper? cutting the performance out of the equation.
    also much more comfortable

    • joe

      An excellent technique — and one I’ve used before. But I think I should plug directly into the pedal for these tests, as opposed to using a reamp, because some of the circuits (especially the Fuzz Face and Tone Bender Mk 1.5) respond best that way. I’ve finished that part of the recordings, actually, and I feel I’ve performed consistently enough to give a fair estimation of the sound of each circuit. 🙂

  • David

    I can’t wait to hear the output of this project! Will it be available as an audio podcast, like your superb booster podcast. That indeed would be awesome!

    Would a Harmonic Percolator meet the criteria of this project too?

    • joe

      That podcast was fun — but this will be a video, because these days I prefer to combine sound with overlaid text, as opposed to blabbering away forever. 😉

      Nope, the Harmonic Percolator is strictly a silicon circuit — though I wonder if you COULD make a germanium version….

  • Regarding a silicon approach with a “lower gain” transistor, can’t you lower the gain in any grounded-emitter stage by just lowering the value of the collector load resistor?

    Mind you I haven’t breadboarded or built any fuzz circuits ever but I’m getting dangerously close to wanting to check it out.

    I’m also curious to know whether these Ge fuzzes suffer from temperature problems and how that manifests itself.

    • joe

      You know, I’ve read about the temperature issues a zillion times, but have never experienced them. However, I live in always foggy San Francisco, where the temperature seldom drops below F45° or rises above F80°.

      Can any Yukon or Sahara dwellers enlighten us here? 😉

  • I recall reading somebody used to keep his ge fuzz in the fridge, because during the open air concert in blistering sun it would stop working.

    My encounter with ge was of entirely different nature. I got hold of a whole bag of NOS ge trannies, and either they were too leaky or in a unsuitable gain range, so nuthin but farts emanated from the circuit.

    Maybe I shoud give it a shot again. Hope I don´t get bitten by the germanium bug as bad as Joe was :smirk:

    • Bebah Palula

      What fuzz circuit were you using? Some of these circuits are self-biasing (as in there is a large resistor connected from collector to base) which tends to keep the transistor ready for action in spite of gain differences.

      “Farting” or “sputtering” would tend to happen if the transistor is either turned off (no current into the collector), or saturated (maximum current into the collector) with no signal input.

  • Bebah Palula

    Assuming it’s this one:


    It seems to be self biasing. RGK’s explanation seems very thorough.

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