The Constellation Vintage Fuzz is an adaptation of the Shin-Ei Companion FY-2, an early 1970s silicon transistor fuzz that was also re-labeled under the brand names Avora, Jax, Kimbara, Thomas and Zenta.
The FY-2 is the slightly-less-famous and often-mistaken precursor to the FY-6, which was best known for being re-branded as the Univox Super Fuzz. The FY-2 does not have the octave effect of the Super Fuzz, but it does have the same scooped midrange character.
The fuzz control of the FY-2 is an odd setup that shifts the balance between the two transistor stages rather than directly controlling gain. Many people wonder whether it’s working right because it doesn’t seem to change the intensity of the effect as it’s turned, just the harmonics and texture. This is how it’s supposed to work. It’s not tremendously useful, so most people just leave it up all the way.
The Constellation project is faithful to the original FY-2, with two additions: 1) a control to allow the characteristic mid-scoop to be dialed back into more of a flat EQ, and 2) an optional volume boost stage before the master volume control at the end. The original unit suffers from excessively low volume, so the make-up gain stage from the FY-6 has been adapted for this circuit. With the gain boost disabled and the Scoop control at maximum, the circuit is 100% identical to a vintage FY-2.