MXR Power 50 Overdrive

The MXR Power 50 Overdrive, also listed as the TBM1, is MXR's signature overdrive pedal for Tom Morello. It captures the sound and functionality of Morello's amp-and-cab setup for use with any rig, whether that is a simple combo amp or a high-end custom stack¹². Morello himself frames it simply: the pedal emulates the amp setup he has used since 1988, the setup behind his identifiable sound on 21 studio albums³.

The pedal launched in December 2021 as Morello's first signature overdrive, and it stands apart from most overdrives by behaving like a full amp front end: six knobs matching his amp's control interface, plus an onboard effects loop configured the way his amp's loop is⁴.

Tom Morello's amp and cab sound in a pedal

Two key elements of Tom Morello's signature sound are his amp-and-cab setup, and the Power 50 Overdrive recreates that setup in pedal form³. The specific rig is his 50-watt Marshall JCM800 2205 head run through a Peavey 4x12 cabinet, an amp setup he has used since 1988⁴⁸. In Morello's own words:

The point of the pedal, as Jim Dunlop presents it, is portability of that sound: it delivers Morello's 1988 amp and speaker cabinet sound regardless of the player's setup³. Delicious Audio describes it as "a bright red pedal that recreates Tom's amp set up and puts it at your toe tips"⁹. For a player who wants the Morello crunch into a clean combo, a modeling rig or a different head entirely, the pedal is designed to get there without the Marshall and the Peavey cab.

The controls

The control interface mirrors Tom's amp, with six knobs: Gain, Bass, Middle, Treble, Volume, and Presence¹. Delicious Audio notes the layout lets you replicate his exact settings⁹. The manual gives the EQ ranges:

The manual lists the Treble control as +7 dB, -21 dB at 5 kHz².

Note where the EQ sits in the chain: Bass and Volume act on the pre-effects-loop signal, and the loop return feeds in before the Presence control and the output tone-shaping¹². That ordering is the same as on Morello's amp, which is the whole idea of the pedal.

The effects loop

Yes, the Power 50 has its own effects loop, and it is one of its most distinctive features. Jim Dunlop describes it as tapping into the raw signal-clipping point prior to the Presence control and the custom tone-shaping at the output¹. MusicRadar explains the logic: Morello runs all his effects pedals through his amp's loop, so the pedal gives players the same arrangement, with adjustable overall level⁴.

The jacks and their behavior, from the manual²:

• SEND jack: transmits the post-EQ signal to the effects loop.
• RETURN jack: breaks the effects loop connection and receives the effects loop output signal.
• The loop signal is only active while the TBM1 is engaged.

Gearnews found the loop more than a gimmick, calling it an added bonus that makes the pedal versatile for complex pedalboard setups⁶.

A MOSFET take on the Marshall JCM800 2205

The circuitry uses MOSFET technology to recreate the preamp stages of Morello's amplifier for what Jim Dunlop calls amp-like performance¹. Guitar World puts it more concretely: MXR employed MOSFET technology to ape the JCM's preamp stages for an amp-like response⁵. MOSFETs are a common choice when a pedal aims to behave like a tube preamp, since they clip in a way that resembles a tube's soft knee, and here they stand in for the 2205's preamp rather than generic diode clipping.

Gearnews ties the design to Morello's era, noting the pedal uses MOSFET technology to imitate the '90s guitar tones⁶. The target is specific: the JCM800 2205 preamp, not a broad "British crunch" voicing, which is what separates the Power 50 from MXR's other overdrives like the GT-OD or the Sugar Drive, neither of which models a particular amp.

For comparison, Marshall itself makes a JCM800 Overdrive pedal inspired by the JCM800 amp, with simple tone controls and a single 1/4" jack output, but without the Power 50's amp-style six-knob interface or effects loop¹⁰¹¹¹².

What reviewers said

Gearnews' writer, who grew up with a JCM800 as his first all-tube amp head, was positive about the core sound⁶:

He paired that with the view that the effects loop makes the pedal versatile for complex pedalboard setups⁶. Delicious Audio's writeup focused on the fidelity of the design, highlighting the loop "configured just like it is on Tom's amp, with the return placed before the EQ and Presence sections"⁹.

Price and availability

The pedal was announced in early December 2021 and was available to preorder at launch⁵. Pricing at announcement:

• US launch street price: $189.99, December 2021⁵⁶
• UK preorder street price: £189.99, December 2021⁴
• Current list price: $129.99 on Jim Dunlop's product listing⁷

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