Fuzz Detective Appendix 1.0

D’oh! I omitted a circuit from the Fuzz Detective video. It’s the germanium version of the Shin-Ei Companion Fuzz FY-2. So here’s a brief Fuzz Detective Appendix.

The silicon version of the FY-2 is a cult item, a nasty little thing best known for its appearance on Jesus and Mary Chain’s Psychocandy album. The germanium version (which I didn’t even know existed until reader Bear pointed it out!) is a very different beast. Most notably, it lacks the silicon version’s signature midrange scoop, delivering a thicker, fatter sound.

As noted in the video, I replaced the stock B50K gain pot with a B5K. (The overall range of tones is pretty much the same, but this way, all the variations aren’t crammed into 10% of the knob’s range.) Construction details and testing procedures are the same as they were for the 12 Fuzz Detective pedals.

The circuit’s most interesting detail is a feedback resistor between the base of the first transistor and the emitter of the second transistor, just like on the Tone Bender “Mk 1.5” and the Fuzz Face. As a result, you get huge variations in gain when you lower the guitar’s volume pot. But unlike those two better-known circuits, the cleaned-up, lowered-volume-knob sound is heavily filtered-sounding, quite different from a clean, bypassed tone. (On a good Fuzz Face, the lowered-volume sound can be almost indistinguishable from a no-fuzz clean sound.) Also intriguing is the super-saturated, proto-metal timbre.

Despite this omission, the response to the Fuzz Detective video has been downright flattering. The Guitar Player guys were super-supportive, as were the forum participants at diystompboxes and freestompboxes.org. (The threads are in the members areas at both sites, visible only to folks who have registered with the sites — which you should do immediately if you have any interest in DIY guitar effects.) The diystompboxes thread included fascinating commentary from such DIY luminaries as Joe Gagan and Mark Hammer — which promptly got lost during a site glitch last week.

These resulting conversation provided TONS of interesting ideas to exploit for my own selfish ends share with you. I’ve got many interesting things in store — but they’re going to have to wait till after the weekend, ’cause I’ve got rehearsals for a couple of very interesting gigs with a favorite artist I’ve never played with before. (I’m not sayin’ who yet, in case she fires me on Day 1.) Details to follow…

10 comments to Fuzz Detective Appendix 1.0

  • Bob

    William Reid also used an FY-8 fuzz wah, which has the FY-6 Super-Fuzz in it. The FY-6 Super is fatter and fuzzier, and that’s what I mostly hear all over “Psychocandy”. Feeds back really easily with the wah pushed forward, which was obviously a plus for them.

  • Shizmab Abaye

    Joe can you provide a link to the schematic you used? As usual I am finding several with significant differences (more than just component value changes).

    The feedback resistor helps to keep the first transistor turned on just a little bit. This is the same goal as the large resistor from collector to base on a single transistor that shows up in a lot of these designs. If you look at the FZ-1 there is no such biasing going on and you get that “gated” sound for lack of a better term.

  • bear

    Hmm. A bit like a pissed off Fuzzrite. You know, especially cranked, it doesn’t grab me as an “OMG must have!” but at the same time I hear a lot of potential. The odd clean-up adds up to some interesting textures available. My fave fuzz sounds lately are pretty low gain and with weird frequency/bandwith limits. So I’ll have to breadboard with this guy.

    In the FSB link I had given in the last thread, the primary germ FY-2 advocate suggested that it, or at least his middle-ground FF/FY-2 mod circuit worked very well with low gain transistors. Since the cranked/compressed end interests me the least, that could work out pretty well.

  • Dave

    OK here’s one for you. I was in Osaka this week and wondered into some guitar shops. In one FAX cabinet was a box carry case outboard effect with a fuzz, variable mid boost, top and low eq switches, top boost and repeater (choppy term). The variety of fuzz tone you could.get out if that thing was insane. Unfortunately so was the price $1480). So wondering what circuit(s) might have been used and if you know of a good clone build? The eq switches were particularly cool giving lots of interesting variation from thin and filtered to thick and slushy…

  • joe

    That’s an expensive fuzz pedal, even for Japan!

    I have no idea what it is, though the fact that it refers to the trem as a “repeater” suggests a Vox lineage.

    It’s pretty easy to turn a Fuzz Face-type circuit into a trem, like so:


  • Dave

    Yep def a vox of some description but solid state. The eq buttons were the real ear opener, think it was pre.fuzz and being set rather than variable freqs made for really cool instant tones

  • joe

    Oh yeah — per-fuzz EQ is definitely where it’s at. 🙂

  • Hendrik

    Hey Joe,
    thanks for the great Fuzz shootout. Personally I really dig the Shin ei the most, especially with germanium transistors. Would You share which schematic You used on this? I find there are quite a few very different ones around.

    cheers from germany,


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