Evidently, among electric guitarists, the sonic thirst for Plexi-style overdrives is hard to quelch.

Athens’ Tsakalis AudioWorks is the latest stompbox builder to release a Marshall-in-a-box pedal inspired by the tones of that company’s legendary tube amps that defined the sound or rock’n’roll.

Using jfet technology, the Room #40 can recreate the tones of several Marshall amps: the Super Lead (1959/1987), the PLEXI™ Super Bass (1992) and the JMP™ and JCM800™ (models 2203/2204), also applying, on-demand, Van Halen’s “Brown Sound” hack – brought to you by the Variac knob, which sweeps the voltage from 7.5V to 21V.

A toggle switch in the middle of the pedal delivers two modes: “19” is the older Plexi-inspired mode, while “22” triggers the more modern JMP™ & JCM800 tones. Each mode has its separate Volume (I and II). A 3-band EQ section + presence allows for ample tone-sculpting.

An extra boost circuit can be controlled via a dedicated footswitch and a internal trimpmot accessible through a hole on the bottom of the pedal.

Hear the sound of the Tsakalis Room #40 in the videos below. We added it to our uber-thorough article about the Best Plexi-Style Overdrive and Distortion Pedals.


Over the years, we have had many different types of Marshall™ amps on our workbench, some for repairs and others for customization. Being huge fans of the sound of these classic amplifiers, that still continues to excite us through the music of so many artists, we decided to try and capture its mojo – the true essence of the soul of this sound – and carefully place it in a little box. Thus the Room #40 was born!
Using jfet technology, we tried to stay loyal to the tone and feel of the following legendary Marshall™ amps: the PLEXI™ Super Lead (1959/1987), the PLEXI™ Super Bass (1992) and the JMP™ and JCM800™ (2203/2204).
We emphasized on emulating the compression and sag coming from the power amp section, when these amps are pushed to the edge, while at the same time giving access to two famous mods, mod #39 (PLEXI™) and mod #34 (JMP™ & JCM800™). Of course the manifestation of our love for the late great Eddie Van Halen, who created the so called “brown sound” using an ohmite variac (variable transformer used to lower or raise the voltage going into the amplifier), could not be absent from this endeavor.
Finally, we incorporated the Presence control to make the sound adjustable to any circumstance, regardless of whether you are plugged into the front of an amp that may or may not have a bright cap or even straight to a power amp.


    • Handmade in Athens, Greece
    • True Bypass
    • 2 types of Marshall circuits PLEXI (19)/ JMP & JCM800 (22)
    • Variac voltage control from 7.5V to 21V
    • Classic Marshall™ 3 band EQ
    • Versatile Presence control for matching pedal to darker or brighter amps
    • Gain Boost controlled by a foot-switch and a dedicated trimmer
    • Power supply : 9V Boss-type DC adapter (center -). Using 10V or more may cause sever damage to the pedal and void the warranty
    • Max power consumption : 30mA @ 9V DC
    • Heavy duty & light weight aluminum box.  73mm(Width) x 123mm(Length) x 55mm(Height)
    • T.A.W. Limited Life-Time warranty