Tsakalis ROOM #40

A Condensed "Marshall Vibe": From Plexi Tradition to the JMP / JCM800 Era

The Room #40 was born from Tsakalis' experience with classic Marshall amps, often encountered in the workshop for repair or customization. The goal is clear: to capture the mojo of legendary heads and make it accessible in a compact pedal, without losing the organic response that makes a pushed stack so charming.

Thanks to a JFET architecture designed to reproduce the behavior of iconic amplification stages, the Room #40 covers both the spirit of Marshall amps without Master Volume (PLEXI Super Lead and Super Bass) and the more modern approach with Master Volume (JMP and JCM800). Two worlds, one signature: from tight crunch to singing drive, with a real amp-under-the-fingers feel.

Who and In What Context Does the Room #40 Make a Difference?

This overdrive/boost pedal is aimed at guitarists who want a big rock sound that's credible without relying on a specific amp. It suits both intermediate players and seasoned musicians, as its controls allow moving from a very dynamic edge of breakup to a denser drive for riffs and leads.

In terms of styles, it excels in blues-rock, classic rock, hard rock, and anything requiring articulate saturation with character. On stage, it can serve as the main drive channel on a clean amp or as a "second channel" on an already crunchy amp. In the studio, it shines for layering guitars: you can quickly sculpt mids and presence to find the right place in the mix.

Two "19 / 22" Modes, Variac, and Boost: A True Preamp in Pedal Format

The Room #40 offers two types of Marshall-style circuits via a selector: the 19 (PLEXI) mode favors openness and vintage grain brightness, while the 22 (JMP / JCM800) mode delivers more perceived gain, compression, and sustain-ideal for beefier rhythms and sustaining solos.

Its 3-band EQ (bass, middle, treble) is complemented by a presence control that's very useful for adapting the treble to the guitar/amp pairing: you can tame a too-bright combo or awaken a darker amp without making the sound harsh. The big plus is the Variac (7.5 V to 21 V): lowering the voltage yields a softer attack and "spongy" compression; raising it results in a tighter, more expansive sound with more headroom and a more "amp-like" feel.

Finally, the pedal includes a footswitch-activated gain boost with a dedicated internal trimmer to precisely adjust the amount of boost: perfect for cutting through the band on leads, thickening a chorus, or pushing the input of an already borderline amp.

The Sound

The Room #40 delivers a Marshall-typed saturation : expressive mids, a clear attack, and that impression of "gritty grain" when picking hard. In PLEXI mode, you get an open crunch, very responsive to guitar volume, which cleans up easily when rolling back the knob. In JMP / JCM800 mode, the texture tightens up, becomes more compressed, with longer sustain and articulation ideal for palm mutes and rock riffs.

The Variac allows fine-tuning the feel: low voltage for more pronounced compression and a "brown" drive, high voltage for a firmer, more defined, and punchier response. The result: a pedal that doesn't just "color" but also reproduces the compression and rebound associated with a pushed amp, while remaining easy to integrate on a modern pedalboard.

Technical specifications

Effects	Boost, Overdrive	Type	sector
Technology	Analog	Use	electric guitar
Format	Pedal	Color	Black
EQ	3 channels

Mode 19	PLEXI	Weight	314 g
Mode 22	JMP & JCM800	Power supply	9 V DC adapter (not included)
Voltage variator (Variac)	7.5 V to 21 V	Consumption	30 mA
Gain boost	dedicated internal trimmer	Power connector	5.5 x 2.1 mm
Input	6.35mm mono jack	Polarity	center negative
Output	6.35mm mono jack	Battery operation	no
Dimensions	12.3 x 7.3 x 5.6 cm