Dr. Robert V3

The Aclam Guitars Dr. Robert V3 is an exceptionally faithful pedal recreation of the legendary VOX UL730 amplifier.

Released in 1966, this innovative hybrid amplifier combined a tube power amp with a solid-state preamp. It is best known for being used by The Beatles during the recording of Revolver and Sgt. Pepper's Lonely Hearts Club Band. Only around 100 UL730 amplifiers were ever built, and very few survive today.

In 1966, VOX introduced a revolutionary amplifier that paired a tube power section with a solid-state preamp. At the time, tube amplifiers were the standard, but they were heavy, cumbersome, and required large transformers. Transistors, on the other hand, were smaller, easier to work with, and far more energy efficient. In 1965, VOX engineer Dick Denney had the idea of combining this "new" transistor technology with a traditional tube power amp.

The new transistor-based preamp allowed the inclusion of two channels, a dedicated 3-band EQ for each channel, distortion, tremolo, and reverb.

Several versions of the UL series were produced, but The Beatles used the 30-watt UL730 and the 120-watt UL7120. Outside of The Beatles, however, these amplifiers saw very little use and many units were eventually returned to VOX. Today, it is estimated that only 20–30 UL730 amplifiers still exist.

The Dr. Robert V3 faithfully recreates the solid-state preamp section of this amplifier. Based on an original UL730 (serial number 3042), Aclam carefully traced the original tag-board circuitry and measured every component value to capture the authentic tone, character, and feel of the original amplifier.

Although powered by a standard 9V DC supply, the pedal internally operates at 18V DC—the same voltage as the original preamp.

The artwork was created by Klaus Voormann, the artist behind The Beatles' iconic Revolver album cover.

The Dr. Robert V3 also introduces the exclusive MACH SCHAU! feature, which was not present on the original amplifier. With its own dedicated Volume and Gain controls, it delivers additional saturation beyond the original UL730, making it ideal for boosting solos or increasing gain on demand.

The phrase "MACH SCHAU!" was famously shouted by audiences during The Beatles' early performances in Hamburg, encouraging the band to deliver an even more energetic performance.

The Dr. Robert V3 is equally at home on bass. The VOX UL400 bass amplifier series used almost the same preamp circuit as the UL730, and Aclam optimized the pedal's FET circuitry to perfectly cover bass frequencies.

Premium-quality components are used throughout, and relay-based True Bypass switching ensures maximum signal integrity.

Dr. Robert V3

Version 3 moves every control to the top panel, eliminating the need for internal trim pots. The FET circuit that recreates the UL730's EL84 power stage has also been improved, and a new LO/HI GAIN mode has been added. LO mode delivers clean, articulate tones across a wide range of guitars and pickups. Pressing both footswitches simultaneously switches between gain modes. HI mode retains the same gain structure as previous Dr. Robert versions.

Features

• The most accurate pedal recreation of the original VOX UL730 amplifier (Serial No. 3042)

• Artwork by Klaus Voormann

• Exclusive "MACH SCHAU!" function (Boost + Gain control)

• Optimized for both guitar and bass

• 3-band EQ

• Relay-based True Bypass switching

Controls

• VOL: Adjusts the output level when MACH SCHAU! is disengaged.

• GAIN: Located in the same position as the Volume control on the original UL730 preamp. Since the original amplifier had no master volume, lower settings produce clean tones, while settings around noon begin driving the FET section into overdrive.

• MIDS: The most important tone-shaping control. On the UL730, the MIDS control is independent of the tone stack, with the signal passing through it before the Volume (GAIN) control. It is then fed into a dedicated gain stage with BASS and TREBLE controls. This allows the midrange to be adjusted independently from the other EQ controls. Turning it counter-clockwise cuts the mids, while turning it clockwise boosts the mids and increases gain. Just like the original amplifier, the MIDS control also drives the FET circuit that emulates the power amp section into saturation.

• MS VOL: Adjusts the output level when MACH SCHAU! is engaged.

• MS GAIN: Adjusts the gain level when MACH SCHAU! is engaged.

• BASS: Adjusts the low frequencies of the FET section.

• TREBLE: Adjusts the high frequencies of the FET section.

• MACH SCHAU! Footswitch: Turns the MACH SCHAU! section on or off. This function is available only when the pedal itself is engaged.

• BYPASS Footswitch: Turns the effect on or off. Pressing both the BYPASS and MACH SCHAU! footswitches simultaneously switches between LO GAIN and HI GAIN modes.