Rocktron aims to capture every era of Plexi tone with new ValveSonic all-tube guitar preamp

Rocktron has announced the ValveSonic Plexi all-tube guitar preamp.

Developed with LA Custom, the preamp aims to nail ‘Plexi’ tones spanning the ’60s to the ’80s and beyond.

A bright control offers five different variations, while a 1-2 switch toggles between modern and classic-style amp inputs.

A variety of boost controls and Rocktron’s Afterburner circuit - which adds an additional gain stage - help to fine-tune the tone.

The ValveSonic Plexi is available now for $799 - head over to Rocktron for more info.

Press release

Each ValveSonic model features a front panel input jack. The 1-2 switch affects the input of the tube stage in the preamp. When switched to “1”, the unit provides the more “modern” type of input used on British style amps. When switched to “2”, the unit provides a fatter, “classic” type of input used on vintage British amplifiers.

The Tight switch is used in conjunction with the 1-2 switch; in the up position the input is “tightened up” much like more modern British amplifiers, while in the down position the tight function is not active.

The ValveSonic Bright control is a six position switch that provides five different bright variations to the overall tone found in British amplifiers, from vintage to modern, with 0 being off and 5 being the brightest.

The Gain control is used to determine the amount of GAIN Input level driving the ValveSonic tubes. Boost can be obtained by flipping the Boost switch to the On position. The Boost works in conjunction with the “+” switch. When the Boost switch is On and the “+” switch is in the down position you will obtain an extra gain stage that replicates the 80’s British type of tone. When the “+” switch is Up, you obtain an additional gain stage and essentially add an entire tube to the front end, replicating the 90’s British amps.

Bass, Middle and Treble controls determine the amount of these various frequencies present in the signal.

EQ 1 & 2 switch replicates the two different style EQs that were used in British amplifiers over the years. In the Up position, (position 1), the “modern” EQ is replicated, providing a more midrange emphasis. In the Down position, (position 2), “vintage” EQ is replicated.

The ValveSonic series features a unique AFTERBURNER switch. This switch works in conjunction with the DRIVE control, providing yet another gain stage after the EQ section of the preamp. When the AFTERBURNER is turned On, this switch emulates a post phase inverter master. When On, you can utilize the Drive control to adjust the amount of Drive present in the AFTERBURNER stage.

The ValveSonic also features HIGH CUT control to adjust the High Frequency cut in order to roll off some of the high end “sizzle” when the high gain is used. The Master control determines the output level of the preamp.

The ValveSonic series has been carefully designed to provide pristine tone, no matter what your style of performance.

Michael Astley-Brown

Mike is Editor-in-Chief of, in addition to being an offset fiend and recovering pedal addict. He has a master's degree in journalism, and has spent the past decade writing and editing for guitar publications including MusicRadar, Total Guitar and Guitarist, as well as a decade-and-a-half performing in bands of variable genre (and quality). In his free time, you'll find him making progressive instrumental rock under the nom de plume Maebe.

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