Vox Valvetronix Tone Lab

The Vox Valvetronix Tone Lab is a Modeling Valve Guitar Preamp from Vox, a spin-off from the company's AD60VT and AD120VT modeling amplifiers. It packs the amp modeling of those amps into a floor unit built around a miniature power-amp stage using a 12AX7/ECC83 dual-triode tube, which Vox calls the Valve Reactor. The idea is that the tube stage shapes the modeled sound the way a real power amp does, rather than leaving everything to the digital modeling¹.

The controls and display

The Tone Lab is presented in a businesslike metal case with Vox-style chicken-head knobs and a small perspex bulge protecting the tube. A plasma display shows patch names of up to eight characters and numbers, and monitors parameter editing¹.

There are seven rotary amp controls:

Beneath the display are ten buttons: four preset selectors for the four patches in the current bank, bank up and down keys, keys for Utility and Global setup modes, a patch write key, and a tuner key¹.

Amp models and effects

The unit offers 16 amp models. Names like Tweed, Black, UK68P, UK '80s, UK '90s, UK Modern, Recto, US High Gain and Boutique leave little doubt about what each model is aiming at¹.

The effects section sits after the amp modeling and is edited with three knobs¹:

• Modulation: five types, including chorus, flanging, tremolo, phaser and rotary. The tremolo has a width control for stereo panning.
• Delay: three types, offering pristine digital delay, simulated tape echo, or multi-head echo with a choice of five "head" combinations.
• Reverb: three types, including spring, plate and room, with controls for high and low damping and the wet/dry mix¹.

Several of the effect models are based on specific circuits. The Wah is modeled on the original Vox V847 wah pedal, and Treble Boost is modeled on the AC30 top boost circuit. U-Vibe is based on the Univibe phase/vibrato pedal favored by Jimi Hendrix, and the Flanger has the same features as the original Electro Harmonix Electric Mistress, including the manual or "parked" flange option. There is also an Auto Wah setting that responds to picking intensity, and an Octave setting, an octave divider that only works with single notes and can dial in one or two octaves below the original signal. An Acoustic Emulation model adjusts the bass, body resonance and treble of the modeled sound¹.

Connections and setup

The Tone Lab has the usual stereo analog outs on balanced jacks, and mono operation is possible by connecting only the left output. A rear-panel slide switch selects between Amp and Line output voicing, so the unit can be matched to a guitar amp or to a desk. MIDI In and Out jacks allow patch dumping or parameter editing from an external device¹.

The built-in tuner's reference A can be recalibrated between 438Hz and 445Hz¹.

History: from the AD60VT and AD120VT amps

The Tone Lab is a spin-off from Vox's AD60VT and AD120VT modeling amplifiers, carrying their modeling and Valve Reactor tube stage into a standalone preamp format. The digital signal at both the input and output converters runs at 20-bit resolution with a sampling rate of 44.1kHz¹.

What the reviewer said

Paul White reviewed the Tone Lab for Sound On Sound in December 2003, checking out the presets using both a Strat and a Les Paul. His verdict on the pros was that it is "Very easy to use," with excellent clean and lightly distorted sounds with lots of life and jangle, and a great effects section¹.

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