Dr. Robert: Replicates the legendary Vox UL730 used by The Beatles
The story behind the Dr. Robert effect pedal
Get immersed & discover the creaton process in the story of a vintage enthusiast and a circuitry master, pursuing the tone that has dazzled countless guitarists around the globe. Learn how this could be achieved in this six-episode documentary full of anecdotes, ups and downs, and eventually the accomplishment of what began as a long-time obsession.
Pursuit of an Iconic Sound,
the Inception of a Long Journey.
Chapter 1
This video marks the beginning of our short serie about Dr.Robert, Aclam’s latest overdrive pedal. In this chapter Marcel and Marc, the two people at the origin of project, take us back to the 60s to explain us how Revolver and the Vox UL series inspired them to create Dr.Robert.
Vox UL series,
Myth or Big Deal?
Chapter 2
Our serie about Dr.Robert overdrive pedal continues with our second episode, “Myth or Big Deal”. Marcel and Marc, original creators of our latest overdrive pedal, discuss about the importance of Vox UL series for the Beatles and the music industry in general.
Amp Hunting: Speculation,
Scam, and Tomatoes
Chapter 3
In the 3rd episode of our serie about Dr.Robert overdrive pedal, Marc and Marcel, creators of Dr.Robert, tell us about their quest to find the UL amplifier. A long path, full of pitfalls, scams, and a lot of patience. Was it a happy ending?
Restoration and
Tonal Harvesting
Chapter 4
The creators of Aclam’s Dr.Robert overdrive pedal are back in action in the 4th episode of our serie. Now that they have finally acquired the amplifier they were looking for, Marc and Marcel can start the restoration process.
Contextualizing the Tone
Chapter 5
Discover in the 5th episode of our serie about Dr.Robert overdrive pedal how Aclam came up with the name Dr.Robert, and the branding process featuring Klaus Voormann, the iconic designer from the Revolver album.
Fitting Pieces Together
Chapter 6
After a year working on the project, Dr.Robert overdrive pedal creators tell us about the challenges and experiences met during the creation process. A great journey that started in Barcelona, but that’s taken inspiration from a lot of places. Discover it now in the 6th and last episode of our serie.
Dr. Robert Features
The most accurate replica of the original UL730 preamp
This pedal is based on the normal channel of the VOX UL730 S/N: 3042. We’ve found some internet and old schematics but major discrepancies between the published schematic and the real thing were detected. We checked every component type and value so we are 100% sure this is the closest you can get to the rarest Vox amp.
Following the preamp there is a custom FET based circuit emulating the saturation produced by the UL730 EL84's tube power amp section.
Additionally, the circuit works with the same voltages the original amp does. Thanks to a charge pump circuit that takes the 9VDC from the battery or power supply and converts it to 18VDC.
Artwork made by Klaus Voormann
We're so honored to have Mr. Klaus Voormann, designer of The Beatle's Revolver cover album, sign the artwork for the Dr. Robert pedal!
Mach Schau! function
Get an extra saturation function via a footswitch with an independent volume control.
Do you know what "Mach Schau" means? That was the most repeated sentence shouted to The Beatles by one of the venue's manager in Hamburg when the energy fell flat.
Smart Track® Fastening System
All our pedals use a custom enclosure designed to perfectly match our Smart Track® pedalboards.
With the side thumb screws attach and lock the pedal into the pedalboard with no risk to loose it or to get robbed easily.
You will also get a high quality Velcro® pad so you can use it on any other pedalboards in the market.
Circuit tailored for both guitar and bass instruments
Although the Dr. Robert is based on the Vox UL730 preamp, the Vox UL400 share with them almost the same circuitry (and these are designed for bass).
By tuning the FET circuit a bit, we managed to make the Dr. Robert pedal suitable for both guitar and bass. No low-end drops, resulting in a perfect preamp and distrortion tool to plug directly to the desk or into an amp.
Same 3 band equalizer via internal treble and bass trim controls
The original VOX UL730 had a 3 band eq: Middle, Bass and Treble.
Middle control is the one that helps to tailor the tone better, that is why this is one of the main controls. You can access to Bass and Treble controls inside the pedal. Check out the internal controls section to know more about this.
High end components
You will find the finest and closest components to the original amp. Dr. Robert has Carbon comp resistors, Nichicon Fine Gold and Wima caps & Alpha pots to make the Dr. Robert a reliable pedal with a superb tone!
True bypass relay switching
We've designed an intelligent trye bypass relay switching which constantly monitors voltage supply. It switches itself to true bypass when detects a drastic drop in voltage, so you will never get any signal interruption even if you battery or power supply fails.
You will also know when the battery has to be replaced 2-3 hours before it completely drains. Both LED's will blink to let you know something is going on.
Dr. Robert tech specs
Dimensions: 13,6 x 8,7 x 5,5cm (5,4” x 3,4” x 2,2”) with knobs
Weigth: 410 gr. (0.9 lbs)
Bypass: Relay True bypass
Power requirements: 9V DC Center Negative 100mA minimum or a 9V battery
Current draw: ≈40 mA
Included: 1 x Anti-sliding rubber pad & 1 x Velcro® pad
Setting up on a pedalboard
Take advantage of our custom enclosure to attach the effect pedal to your pedalboard.
We incorporated a proprietary locking system which allows the user to fasten the pedal without the need of using the typical hook and loop method. This custom fastening system follows the same philosophy behind the Smart Track fasteners but integrated in the enclosure reducing the space occupied by each pedal.
That translates into more pedal density for the same space, and who doesn’t want that? We strongly recommend you to take a look at our line of pedalboards, which are the best complement to our pedals!
Velcro pedalboard
Take the included super strong Velcro® pad and stick it on the base plate. Again, make sure the base is clean of dirt and dust.
Smart Track pedalboard®
Add the anti-sliding rubber pad at the bottom of your pedal, specially shaped for this unit. Surface must be clean and dry before applying adhesive pad.
Loosen the 2 thumb screws to unlock the bottom pieces out of the pedal. Place the pedal, inserting the bottom pieces inside the grooves.
Move the pedal to its final position. Tighten the two thumb screws with your hands or with a screwdriver.
DIY woodboard
You can screw the pedal directly to your pedalboard with wood bolts through the enclosure side holes.
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Controls
Int. controls
Dr. Robert audio samples
Paperback Writer
Epiphone Casino
Gretsch 6120
Gretsch 6120 PepBox
She said she said
Epiphone Casino
Gibson SG
Rain
Epiphone Casino
Dr. Robert
Epiphone Omni
Taxman
Strato Omni
Taxman (solo)
Stratocaster
Sgt. Peppers (Rythm)
Epiphone Casino
Sgt. Peppers (Lead)
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Epiphone Casino Solo
Fender Stratocaster Solo
What it's said about the Dr. Robert effect pedal
The Dr. Robert is no one-trick pony. Its overdrive, fuzz, and boost
"The tones within are so close to the Beatles tones I’ve been chasing for decades, and so unique in non-Beatles contexts."
Premier Guitar (Premier Gear)
The Dr. Robert is a bit of an art piece as well
“The cool-sounding is a worthy and interesting addition to anyone’s stompbox collection.”
Guitar Player
.
"Here's your prescription to replicate The Beatles’ Vox UL 730 amp sounds"
"An obscure and largely forgotten amp gets rightly put back on the map in a versatile drive pedal with visceral power and a raw grind that will find a role in many kinds of music."
Guitar World
Sonically, the Dr. Robert is a joyous experience.
“Pushing up the gain yields a surprising amount of grind and sustain. Kicking in the “Mach Schau” boost takes things into another level entirely.”
Interactive Guitar magazine
.
This pedal is just what the doctor ordered.
“Custom FET circuitry provides the sag and sound of tubes, while the middle control increases the sweet saturation effect.”
Maverick magazine
Not just for Beatles fans, but definitely for Beatles fans.
“The llustration by “Revolver” cover artist Klaus Voorman really brings that spirit and feel of those classic LPs back to life, and the sounds fit perfectly as well”
Pedal of the day
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From BARCELONA to the Planet 
Works well, but not perfect
It works well for a variety of power supplies, but I think the grip part needed to be wider to give more surface area. Also, the bolt could have used a second nut to help prevent it from unwinding over time. Minor...
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