Seymour Duncan SFX-02 Tweak Fuzz

SeymourDuncan-SFX-02-Tweak Fuzz

What is it?
Seymour Duncan SFX-02 Tweak Fuzz from the first Seymour Duncan effect series. Possibly from mid 00’s.

The  first series of stompboxes from highly regarded pickup manufacturer? Sure i wanted to see what was going on for myself. I believe the number of manufactured units is rather high and since most of the designs in this first series were priced neatly, they were bound to sell some. But my guess is still – not enough. As we’ve seen with various brands, if a design is a hit, it will stay in production for ages. Wonder if we’ll see a reissue of this at some point. Chances are, no, but still. It would be interesting.  Once i got mine, i took it out for a spin. And tore it open, as usual.

SeymourDuncan-SFX-02-Tweak Fuzz-guts1

There’s two small boards stacked inside. Other for controls and other for the main circuit. Boards are fastened to the box with  pots and jacks. Not a bad thing to see. There’s true bypass switching in place with industry standard three pole switch. Neatly done either way. The battery slot isn’t too easy to access and requires one to remove the bottom plate and its four screws to reach it. But then again. Who uses batteries anyway..

There’s been a traced schematic around for years. Couldn’t find it right of the bat, but one should be able to find it through internet archives with little detective work. It’s Analogguru’s work (and truly amazing work indeed) and it shows us what this thing is made of. The “tweak” control is the key. This control simply changes the value of the input cap from thin sounding small value to fat sounding, larger value. Rest of the circuit is slightly tweaked Fuzz Face.

SeymourDuncan-SFX-02-Tweak Fuzz-guts2

And since it is nothing more but a silicon Fuzz Face, it suffers from the same culprits this classic circuit has always suffered. This being the mediocre output level capability with modern output guitar pickups. But that’s at least partly, compensated with sturdy feel and decent looks. Switchable input cap for a classic circuit may not be enough to create an individual hit.

How does it sound?
Really good. The classic Fuzz Face sound with six different tone settings from thin and nasal to big and fat. Actually, i hear no difference between this unit and quite a few higher end/boutique FF derivatives. And the tone of that blue Dunlop reissue is in tact. This truly shines with single coils or humbuckers with vintage output (less than 10K). For the availability and price, this is very tempting alternative for current big boxed FF reissues. My guess is that these will have their reputation and price  going up in the future. Or this could be one of many slightly tweaked derivatives that will simply be forgotten. Only time will tell.

3 responses to “Seymour Duncan SFX-02 Tweak Fuzz”

  1. first of all. I LOVE your site. absolutely brilliant! i have a tweak fuzz and love it. i don’t think today’s kids understood it or knew how to use it. i use it with everything; 335, strat, even nylon string classical guitar. using guitars volume is essential in getting it’s full potential. i would definitely like to consult with you sometime about a custom build.

  2. Found one of these in excellent condition for $45 about a year and a half ago, amazing score. Great pedal and solid construction. It doesn’t seem to play well with certain pedals, such as my Hall of Fame reverb and an old MXR Distortion + I used to own, but other than that, it’s some sweet, sweet fuzz.

  3. I’m interested in making one of these. I’ve found the schematic, but there appears to be uncertainty over the fuzz pot value. Any chance you could have a peek inside and let me know. Also are 2n3904 and 2n4401 the correct transistors? (Or point me towards the best site covering a DIY build). Cheers.

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