Aclam Guitars Dr. Robert Overdrive

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The Aclam Guitars Dr. Robert Overdrive v2.0 is the very latest version of Dr Robert, and has some nice updates, that its fans were craving...

• Relay-based, true bypass switching, with soft touch switches, for a quiet, clickless feel.
• Removal of the calibration trimmers, so every Dr. Robert is now more consistent than ever.
• A new Gain Trimmer for the Mach Schau function, so now you can tweak its tone a little bit more, and make it less aggressive if you desire.

The Aclam Dr. Robert Pedal 2.0 from Spain Nails the tone of the Vox UL730, one of the rarest amps of all time, used by the Beatles on their iconic Revolver and Sgt. Pepper's records. Plus, this pedal's artwork is created by Klaus Voormann, the designer of the Beatles Revolver LP!


"There are sounds (on Revolver) that nobody else has done yet. I mean nobody... ever."
- Paul McCartney


Dr. Robert... what is it?
 Dr. Robert is Aclam’s newest guitar pedal, that gives you a perfect replica of the legendary Vox UL730 amp sounds, famously used by The Beatles, Stones, and Zeppelin!
 
QUICK FEATURES:
• Mach Schau! - Extra saturation function (click both footswitches on)

• Smart Track Fastening System
• High-end components
• True Bypass switching
• The closest you can get to the rarest Vox amp

OVERVIEW:
The Vox UL700 amp series were the secret weapon used by The Beatles to achieve the unique guitar tone on Revolver and part of Sgt. Peppers. They were also used by The Rolling Stones and Jimmy Page of Led Zeppelin.



Introduced in 1966, these state-of-the-art guitar amps mixed a solid-state preamp with a tube power amp section. Tubes were standard at that time but had the inconvenience of being voluminous and prone to fail, plus they needed bigger transformers due to impedance matching and power requirements.

Transistors were the solution as they were way smaller, reliable and took much less energy to operate. So, in 1965, Vox engineer Dick Denney decided to develop a hybrid amp with a solid-state preamp and tube powered amp section.



Thanks to the relatively new transistor technology, lots of features could be added. Top-of-the-line models included two channels with 3 band eq each, distortion, tremolo and reverb. There were many variants with different power ratings, but the ones used by The Beatles were the UL730 (30w) and UL7120 (120w).

Unfortunately, aside from The Beatles, those amps weren't popularly used at the time and most of them ended being returned to Vox for their disposal.

 Only a small number of UL730 units survived (around 20/30 units as some renown Vox connoisseurs state), attaining the title of being the most collectable Vox amps, with prohibitively collector pricing. Now they are the missing link between tube and solid-state amps.

 The Dr. Robert is based on the Normal channel of our Vox UL730, serial number 3042. We traced the original tag board circuits and measured each component’s value to make the closest replica of the amp’s soul and character.


One of the keys of its tone is the “Middle” control, which is one of the most interesting mid-range eq ever found on an amp. By turning it counterclockwise, a great amount of mid-frequencies will be subtracted, creating a scooped sound. On the other hand, when it's turned clockwise it will bring out all the mids, and the signal will build up in gain. By tailoring the “Middle” knob you can control both midrange and saturation.



As the solid-state preamp of the UL730 doesn’t create much distortion by itself, Aclam has coupled it with a custom FET saturation engine to mimic the attributes of the tube power amp section. Not happy enough with that? We’ve gone even further, creating the “Mach Schau!” section (click both footswitches on), which adds saturation to your main sound and includes an independent volume control to allow you to have both a rhythmic and a solo tone.
 
FEATURES:
Sometimes you can’t trust the internet or an old schematic. We’ve found major discrepancies between the published schematic and the real thing, such as component types and values, so we can assure you that this is the closest you can get to the rarest Vox amp.

Following the preamp there’s 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 found on the original amp, thanks to a charge pump circuit which takes the 9VDC from the battery or DC plug and converts it to 18VDC.


Smart Track Fastening System:

All Aclam pedals use a custom enclosure designed to match perfectly with our Smart Track pedalboards. Using the side thumb screws, you’ll be able to safely lock the stompbox into one of our pedalboards. It was also designed with other pedalboard options in mind.


Mach Schau! Function:

The Mach Schau! is a function that you can activate by clicking on both footswitches. It provides extra saturation with an independent volume control (MS Vol). The Mach Schau! is like a distortion preset. You will have the base sound with more or less saturation, and from that sound, when you activate the Mach Schau!, you will get even more saturation. With the independent volume control, it allows you to have more distortion at the same volume, or the same distortion raising the volume.


Custom graphics by Revolver's cover artist, Klaus Voorman:

We’re so honored to have Klaus Voormann, designer of The Beatle’s Revolver album cover, create the artwork for the Dr. Robert pedal!


High end components and true bypass switching:

We made an extra effort to put the finest and closest components to the original amp in the Dr. Robert pedal. Carbon comp resistors, Nichicon Fine Gold and Wima caps, Alpha pots and switches, these make the Aclam Dr. Robert pedal reliable, with authentic tone.


Circuit tailored for both guitar and bass instruments:

Although based on the UL730 preamp, the UL400 series (designed for bass) shared almost the same circuitry. When doing tests using different instruments and amps, we noticed that Dr. Robert sounds flawless with bass too! By tuning the FET circuit a bit, we managed to make the Dr. Robert suitable for both guitar and bass. There are no low-end drops, resulting in a prefect preamp and distortion tool to plug direct or into an amp.
 
CONTROLS:

BYPASS SWITCH:
Engages the unit allowing the signal to flow through the Dr. Robert circuit. It also lights up the LED above it.



VOL:
Controls the overall volume of the Dr. Robert when you’re not using the Mach Schau! section.



GAIN:
This control is placed in the same position of the circuit as the original UL730’s volume control. Since none of the Vox UL series had a master volume control the user had to turn it all the way up to bring the amp into saturation, and believe us, this thing is loud. To solve that, we put the Vol control at the end of the FET section, so now the volume control on the original amp turns into a gain knob on the Dr. Robert. At lower settings, the Gain knob will produce a clean tone, but as you approach the 12’o-clock mark, the FET section will start entering the saturation region. Have in mind that due to Dr. Robert’s great dynamics, different types of guitars and pickups will affect the clean range of the Gain knob.



MIDS:
This is the most critical knob to tailor your sound. Unlike most equalizer circuits (which get placed after or before the volume control) Vox separated the mids control from the rest of the tone stack in the UL730. In this preamp, the signal gets amplified first, followed by the Middle control before the volume pot. After this, Vox placed a special gain stage, coupled with the Bass and Treble controls. Thus, you can control the midrange without interacting with the rest of the eq, as traditional tone stacks do. By turning it counterclockwise, it will subtract a great amount of mid-range, creating a really interesting scooped sound. Turning it clockwise will bring mid frequencies and the overall gain builds up hitting harder the EL84 tubes, creating saturation. Just like the real amp does, Dr. Robert’s “Middle” control has the same behavior, thanks to the FET section specially tuned to mimic the power amp saturation on the UL730. So, keep in mind, the “Middle” knob will have a great effect on the overall saturation of the unit.
MS VOL:
Independent volume control for the Mach Schau! section.



MACH SCHAU! Switch:
Activates the Mach Schau! Section. It also lights up the LED above it. (Note that the Mach Schau! function works only when both footswitches are activated). This function is not an independent overdrive, but an extra tone of Dr. Robert’s main circuit).
 
MORE INFO:

Power Sources (sold separately):

Uses a standard 9 volt battery, or a 9V DC Center-Negative 100mA minimum power supply (like Boss and most all other guitar pedals use).

Warranty:

This product comes with Aclam's 2-year warranty.

Specs:

Dimensions: 5 3/8" x 3 1/2" x 2 1/4" (including knobs)

Bypass: True bypass

Current Draw: minimum 40mA
SHIPPING:
Ships fast! Usually same day, with Free 2-Day UPS Shipping in U.S. with tracking (1 biz day processing, 2 biz days transit time, guaranteed).

Cool Guitar Shop's added value when purchased here on Reverb:

• Lowest Price Allowed by Aclam in the U.S.
• Fast Free Shipping in U.S.
• No Risk: Try it on your own rig for 30 days. Don't love it? Return it for a full refund... no hassles, no costs. (We'll send you a prepaid return label link.)
  
• Rock-solid customer service, 365 days a year

Craving that late 60s, Vox UL730 Beatles Revolver sound? Dr. Robert will see you soon.