The Zircon is Aion FX’s take on the Hot Silicon fuzz – which is of slightly disputed origin, but we’ll leave that well alone.  

It’s a silicon Tone Bender MKII, with a Big Muff style tone control.  

Aion build docs, including schematic and biasing tips can be found here. 

AION FX ZIRCION / HOT SILICON – VERO LAYOUT