The Runoffgroove Supreaux Deux is an updated version of the Supreaux circuit, a JFET adaptation of the Supro 16T amplifier. The original Supreaux circuit, originally designed in 2004, is well-known as the source circuit for the JHS Superbolt and is also available as a PCB from Aion FX.
The Supreaux Deux was designed in 2008 in order to be more accurate to the sound of the Supro amp. As the original circuit had grown in popularity, the Runoffgroove team decided that they could do better, and the end result is something that they felt was even closer to the original amp’s character.
The Aion FX version of the Supreaux Deux is a direct adaptation of the original circuit, but with two modifications. First, since the original circuit needs 18V power to sound right, a charge pump has been added to get 18V from a standard 9V input. In addition, another position has been added to the Bottom switch allowing for three settings instead of two.
Since the J201 is very difficult to find in TO-92 through-hole format, and many DIY hobbyists are intimidated by SMD parts, Aion FX offers J201s in SMD format that have been pre-soldered to adapters so they can be used as through-hole parts.