Massive Unity Ltd. Dirty Boy

The Massive Unity Ltd. Dirty Boy is a preamp, boost and overdrive pedal in a compact stompbox format, first shown at Summer NAMM in June 2018¹. Designed by Danny Gomez with the Massive Unity Ltd. team, it is a "powerful, clean-looking but dirty-sounding effect" that packs a full analog preamp section, a footswitchable boost and a speaker-emulated output into what Pedal of the Day called an ultra-compact, gig-ready design².

What makes the Dirty Boy unusual for a drive pedal is how it is meant to be used. It runs best in an amp's effects loop, where it can replace the amplifier's own preamp section¹, and it can also serve as a preamp in your amp's effects loop or as a standalone dirt pedal on your board³. Under the hood is Gomez's proprietary T.A.E. (Tube Amp Emulation) technology, an analog approach to recreating the sound of real tube drive²¹.

A clean-looking, dirty-sounding analog preamp

The Dirty Boy is fully analog. It uses an analog circuit to mimic the tone of tube amps, in the model favored by Blues Saraceno, together with a closed-back 4x12-inch Greenback cabinet³. Pedal of the Day described it as "lightweight, all-analog and gig-ready out of the box"².

The pedal works in two different modes², and its two outputs serve two different jobs:

• Preamp output: delivers the raw sound of the preamp, for feeding a power amp and speaker setup⁴.
• Emulated output: carries a speaker emulation based on a closed-back 4x12 loaded with Greenback speakers, so you can go straight into a mixer, interface or recording setup without a cab¹⁴.

Guitar World's Trevor Curwen, reviewing the later Dirty Boy preamp that grew out of this design, found the sound "all nicely responsive to playing dynamics with smooth volume knob clean-up" and listed "excellent sound quality" among the reasons to buy it⁴.

The controls and jacks

The control layout is simple. The Dirty side of the pedal carries Gain, Tone and Volume controls², with one more control for the foot-switchable Boost¹. The Boost section is also footswitchable and independent of the Dirty side, so you can stack it or use it on its own².

There is also a jack for external control, so an expression pedal can be connected to sweep parameters hands-free².

T.A.E. and the Variac simulator

T.A.E. stands for Tube Amp Emulation, Danny Gomez's proprietary technology for recreating the sound of real tube drive²¹. It is the core of the Dirty Boy's design and appears across the family of pedals associated with Gomez, including the later Dirty Boy preamp and the Warm Audio Dirty Boy Jr. series²³.

The Variac simulator is the control that "keeps things intriguing," as Pedal of the Day put it when reviewing the later Dirty Boy preamp, "with a wide range to explore"⁵. On the related Dirty Boy Jr. Overdrive, the Variac control is described as a voltage-starve control, letting you pull back the voltage feeding the circuit and change its character⁶. A Variac, in amp terms, is a variable transformer used to raise or lower the voltage feeding an amp, and the pedal's control emulates that effect.

From Blues Saraceno's amp to the Dirty Boy

The Dirty Boy's circuit traces back to a family story. It is based on the amp used by guitarist Blues Saraceno, which was built by his father, Alex Saraceno². Alex Saraceno began by building one-off circuits for his son, and that work grew into the Dirty Boy brand⁷. The new Dirty Boy Preamp is a Gomez design, but it was based on an amp designed by Saraceno Sr. for Saraceno Jr.⁸

The lineage runs forward as well as back:

• The Dirty Boy T.A.E. Preamp Boost/Overdrive, the predecessor reviewed by Pedal of the Day in December 2018, carried more features than the later Dirty Boy preamp⁵.
• The Dirty Boy brand was later acquired by musician and product designer Danny Gomez, known for his proprietary T.A.E. technology⁴.
• Warm Audio later partnered with Dirty Boy to rebuild the preamp circuit into the pedalboard-friendly Dirty Boy Jr Overdrive, alongside Jr. Booster and Jr. Fuzz models⁹⁶.

Guitar World, naming the Dirty Boy preamp among its 30 best new pedals of the 2020s, noted that it "features two outputs. The first delivers the raw sound of the preamp for use with a power amp and speaker," while the second carries the Greenback-based speaker emulation⁹.

Where it sits among preamp and drive pedals

For a player comparing the Dirty Boy with a conventional overdrive or distortion pedal, the difference is intent: the Dirty Boy is a preamp first, designed to stand in for an amp's front end in an effects loop or to feed a power amp directly, with a speaker simulation output for going straight to a desk. Its boost section adds a boost stage that can be used independently, and its expression jack opens it to external control in the way players more often expect from expression pedals on modern boards²¹³.

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