Many distortion stompboxes are essentially clones of pedals that became famous decades ago. Relatively few are based on guitar amplifiers. Aclam’s Dr. Robert takes a different approach by featuring a Normal channel that replicates the front end of the Vox UL730, a 30-watt hybrid amp developed by Vox cofounder and designer Dick Denney and introduced in 1966, which coupled a solid-state preamp to a tube output stage.
The UL730 and its 120-watt sibling, the UL720, were used by the Beatles on Revolver (which features this pedal’s namesake track, “Dr. Robert”) and part of Sgt. Pepper’s Lonely Hearts Club Band. Jimmy Page and the Rolling Stones had a go with the amps as well. Even so, they flopped so badly in the marketplace that reportedly most of the UL production was returned to Vox for disposal. Brutal!
Aclam says it based the Dr. Robert’s Normal channel on one of the lucky UL730s that escaped the sledgehammer, and which now resides at the company’s headquarters in Barcelona. Aclam engineers traced its original circuit, explaining that they “measured each component’s value to make the closest replica of the amp’s soul and character.”
The dual-channel pedal also features a global midrange control. It provides the same extreme EQ shaping of the amp’s mid circuit, allowing you to sweep from a scooped sound, with the knob fully counter-clockwise, to maximum midrange enhancement with an accompanying gain boost when the control is turned fully clockwise.
True to form, the preamp doesn’t generate much distortion on its own, so Aclam paired the Normal channel with a custom FET saturation stage to mimic the attributes of the amp’s tube power amp section. Even so, tested with a Reverend Gristlemaster T-style guitar and a Danelectro ’59XT12, there was enough grind for crunching riffs once the gain, volume and middle controls were maxed. I also liked how it fattened up the tones through a Fender Deluxe Reverb and a Vox Mini Superbeetle. However, to give the Dr. Robert more saturation, the designers added a foot-switchable gain boost called Mach Schau! The phrase, which is a German idiom for put on a show!, is what club owner Bruno Koschmider would shout at the Beatles when they performed at his various Hamburg hot spots in the early 1960s.
At any rate, hitting the Mach Schau! switch with the corresponding MS! volume knob turned up will increase sustain dramatically and make the pedal very suitable for solos and heavier rhythm playing. The midrange control is all powerful, allowing you to dial in anything from tones with very reduced mid-frequency content (though not exactly “scooped” in a modern-metal sense) to a thick muscular, mids-forward roar. And if the factory bass and treble settings need any tweaking, you can make those adjustments inside the housing via a pair of trimpots. The bottom plate also has to come off if you wish to install a nine-volt battery.
The Dr. Robert is a bit of an art piece as well, featuring graphics by none other than Klaus Voormann, who designed the Beatles’ Revolver album cover such a long time ago. There’s even a sticker in the package with an enlarged view of the hand that Voormann drew reaching out toward the pedal’s bypass LED.
Lastly, the Dr. Robert’s aluminum enclosure features the unique Smart Track fastening system, in which captured thumbscrews on each side of the pedal allow it to be securely mounted to an Aclam Smart Track pedalboard — no locking tape needed. Smart indeed, and just another reason why the cool-sounding Dr. Robert is a worthy and interesting addition to anyone’s stompbox collection.
PRICE $320 street
CONTROLS Gain, volume (Normal channel), MS volume (Mach Schau! channel), global middle control, internal bass and treble trimpots.
SWITCHING Bypass and Mach Schau! I/O Input, output, external power jack
KUDOS Cool sounding replication of a rare Vox amplifier preamp circuit. Mach Schau! Gain-boost function. Smart Track locking system.
CONCERNS A bit hissy at high gain and volume settings, but that’s to be expected from a vintage-style circuit