Tsakalis Audioworks Room #40 — Marshall Plexi & JCM800 | JFET | Variac | Handmade Greece

Tsakalis spent years working on Marshall amps — repairing them, modifying them, learning exactly what happens inside the circuit when they're pushed hard. The Room #40 is what came out of that. Two separate Marshall-derived circuits in one pedal, built with JFET transistors specifically tuned to capture the compression and sag that happens in the power amp section when those amps are driven to the edge — the part most amp-in-a-box pedals skip over.

Mode 19 is the non-master-volume Plexi territory — Super Lead (1959/1987) and Super Bass (1992). The kind of amp where you set the volume and the amp decides the rest. Mode 22 covers the JMP and JCM800, the master-volume era where you can push the preamp harder without necessarily blowing out the room. Each mode has its own Volume I and Volume II controls, which interact the way the channels on a jumpered Plexi actually interact. The Variac knob is the unusual one — it adjusts the internal voltage from 7.5V up to 21.5V, simulating the effect of running a Variac transformer on the amp. This is how Eddie Van Halen got the brown sound, and the control actually does something useful here rather than being a gimmick.

Full 3-band EQ plus Presence. Dedicated boost footswitch with an internal trim pot for setting boost level. Handmade in Athens. True bypass. 9V DC.

Master, Variac, Vol I, Vol II, Bass, Middle, Treble, Presence. Mode 19/22 toggle. Boost footswitch.