|I acquired a Shin-Ei FY-2 fuzz in 1992 or so. I had bought it for $20 from a second hand store, largely because it had a decent case and stompswitch and buying either of those where I was living at the time would have cost me at least $30. Having a naively lesser opinion of 60's fuzzes at the time, I ripped the circuit board out and built another circuit into the box. The original board sat around for a decade or more until someone finally posted information that let me reconnect the pots to it and fire it up. |
Boy was I glad I did. The thing is nasty, sick, fierce and all the other things you want a fuzz to be. It is also a little more maleable than one would think, and VERY easy to build. The unit uses 2SC536F transistors. The F-suffix indicates 536's with hfe values in the 180's to 240's or so. The transistors on mine were around 250, but the values on one I built from scratch were 220 and the difference appears to have no impact.
The stock unit employs a passive mid-scoop filter between the fuzz-generating circuitry and output level control. While this injects the right amount of sinister tone (like a Superfuzz), it isn't always what you want. The scooping depends on passive loss through a 0.1uf cap. If you reduce the bleed through that cap to ground, you end up increasing the lower and upper mids and increasing the "body" of the sound. I inserted a 50k pot on mine (shown in the schematic) between the 0.1uf cap and ground. Alternatively, if the entire scoop circuit is bypassed and replaced with a fixed value resistor, you get the "full bandwidth" fuzz tone without any tone shapping.
The MP3 file provides comparisons between two FY-2 units. The first is an original, and the second is a home-build clone. What you hear is (in order):
- single note, original board, stock, minimum fuzz
- single note, original board, stock, maximum fuzz
- single note, original board, scoop bypassed with 33k resistor, minimum fuzz
- single note, original board, scoop bypassed with 33k resistor, maximum fuzz
- single note, clone, max fuzz, passive bleed through midscoop varied
- A-chord, clone, max fuzz, passive bleed increased over chord
- A-chord, clone, max fuzz, passive bleed decreased over chord
All samples recorded with neck+bridge pickups directly into a Roland UA-30 USB interface. No other devices were involved. Though the volume level on the fuzz was set the same all the way through, there are some pretty substantial volume changes so don't crank it up too loud until you've heard the whole sample.