Dr Robert LTD Edition

The Vox® UL700 amp series are mostly known to be 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, Joy Division and Jimmy Page of Led Zeppelin. But
One UL700 amp was also a crucial piece of gear during the recording sessions of Led Zeppelin’s “II” album. It can clearly be heard on songs like “Whole Lotta Love” and “The Lemon Song”. 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 three 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 and Led Zeppelin, 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 S/N: 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 “Mids” 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 “Mids” knob you can control both midrange and saturation.

As the solid-state preamp of the UL730 doesn’t create much distortion by itself we’ve coupled it with a custom FET saturation engine to mimic the attributes of the tube power amp section. Not happy with that, we’ve gone even further creating the “Mach Schau!” (Renamed “Rock’n’Roll on this special edition) section, 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.