Review: Colby Amps Dual Tone Booster DTB 50

October 7th, 2013

By Eric Frigo

In this day and age when one can gain entry into the boutique amp field simply by purchasing and assembling a predesigned kit, Mitch Colby is the rare builder whose experience in the craft spans more than five decades.

As a product specialist (and subsequent VP and CMO) at Korg from 1978 through 2010, he played a role in developing many Marshall and Vox amp designs. What’s more, as a noted collector and avid tinkerer, Colby has owned, studied, repaired, and restored most of the classic amplifiers on every player’s bucket list.

In creating Colby Amps, his goal was to distill his wealth of experience into a new bespoke line of amplifiers (developed with guitarist Jim Weider) and—since he was no longer hamstrung by the requirements of mass production—to make no compromises in the design or sourcing of materials. The American-voiced Dual Tone Booster DTB50 and DTB100 amplifiers are the company’s first two offerings, and they are a testament to this approach.

The 6L6-powered DTB50 head submitted to Guitar Aficionado was accompanied by an oversized but, at 34 pounds, extremely lightweight open-back 1×12 birch cabinet loaded with a Celestion G12-65 speaker. The amplifier features two fully independent clean and overdrive channels, each with a bright switch and mid-shift control that changes the amp’s tone network for a thicker voicing. Both channels boast controls for volume, treble, mid, and bass, while the overdrive channel adds gain and master volume controls, a bass boost switch, and two switches to engage the individual boost stages (both boost modes as well as channel switching are foot switchable). A single, shared presence knob and channel switch completes the picture.

Tested with a Gibson Custom Les Paul and Fender 1956 Telecaster Reissue, the DTB50 produced a dizzying array of powerful clean and overdriven tones that will make more than a few players ditch their meticulously assembled pedal boards in favor of plugging straight into the amp. The clean tone is full-bodied, powerful, and free of nasty transients, and the boost section has a wonderful Larry Carlton “Room 335” tone reminiscent of the best—and most stratospherically priced—Dumbles. The Colby circuit’s responsiveness to picking dynamics and playing approach is refined but nervous, like a great sports car. It’s a hands-down winner from a pair of hands that have seen more tube sockets and resistors than most.

LIST PRICES Head $3,800; cabinet, $650
Colby Amps,