Dr. Robert: Replicates the legendary Vox UL730 used by The Beatles

The Dr. Robert is a guitar overdrive pedal based on the Normal channel of our VOX UL730 S/N: 3042. This amp in a box pedal was designed to be the closest replica of the amp’s soul and character. A meticulous process of tracing the original tag board circuits and measuring each component’s value has resulted in a sonic approach never reached before. 


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.


Test the Dr. Robert


Int. controls


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 requirements9V DC Center Negative 100mA minimum or a 9V battery
Current draw: ≈40 mA
 Included: 1 x Anti-sliding rubber pad & 1 x Velcro® pad

Download the Dr. Robert user manual


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 - The Beatles audio samples

Paperback Writer

Epiphone Casino

Gretsch 6120

Gretsch 6120 PepBox

She said she said

Epiphone Casino

Gibson SG


Epiphone Casino

Dr. Robert

Epiphone Omni



Strato Omni

Taxman (solo)


Sgt. Peppers (Rythm)

Epiphone Casino

Sgt. Peppers (Lead)

Epiphone Casino Solo

Fender Stratocaster Solo


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 attach effect

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.

how to attach aclam pedal to smart track pedalboard

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.


Demos and reviews of the Dr. Robert pedal

What customers think about our products?

Dr. Robert

06 Nov. 2020 kane russell

WOW ????

This pedal is amazing !! I ran it through a marshall dsl40cr and it just sounded stellar???????? It also plays great through the vox mini super beetle ... from suttle glossy chime to solid grit this thing is great...

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Dr. Robert

01 July 2020 Chang Ling Fatt

Must own pedal!

I bought the pedal through online store. Customer service is very responsive and friendly. The delivery via Fedex was faster than expected. I played with the pedal non-stop after receiving. It is a faithful recreation...

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Dr. Robert

18 March 2020 Paul Carey

exceptionally good distortion pedal

Sure, there is the direct Beatles influence in designing this pedal, which is part of what made me get it, but there is really much more.Ive always loved those sounds on Revolver and Sargent Peppers and never...

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Dr. Robert

28 Jan. 2020 richard bondel

Dr Robert

It seems like a lot of money for a distortion pedal but it offers something different and it's very well made. You have to remove the back to access the battery compartment, which is time-consuming, but you get to see...

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Dr. Robert

27 Nov. 2019 Ola Göransson

Special pedal

It’s rare that I buy a pedal that gets more than occasional usage. Especially overdrives. This one, however, is So good it could be constantly engaged. With the eq function it is really versatile

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Dr. Robert

08 Nov. 2019 William Richins

Dr Roberts pedal

Another great pedal from a company that exceeds customer expectations.

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Dr. Robert

16 Oct. 2019 Daniel Carollo


great pedal and service

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Dr. Robert

28 Aug. 2019 Richard Lloyd

Great pedal

Sounds amazing and works great. Have yet to run through all it’s paces. Very easy interface. No retreat on this purchase

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Dr. Robert

27 Aug. 2019 Drew Cole

Very satisfied

I’m giving this product a five out of five. The sounds are extremely authentic and paired with the right pick ups it’s dead on perfect. The packaging is fantastic and the box comes with beautiful touches and a...

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Dr. Robert

06 Aug. 2019 Robert Gonzalez

Dr. Robert

Beautiful pedal! Really gets the 7-series sounds I've been chasing all these years. Aclam customer service is excellent!

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Dr. Robert

06 Aug. 2019 Graeme Wells

Dr Robert Rocks

This is an amazing Pedal. Authentic & Versatile. Blown away.

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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)

Read this review 

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

Read this review 


Guitar world logo

"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

Read this review 

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

Read this review 


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

Read this review 

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

Read this review 


Get Inspired With The Dr.Robert Playlist


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