VoxValvetronix ToneLab

By Art Thompson With its introduction of the Valvetronix series amps in 2002, Vox upped the ante in the digital-modeling game with its proprietary Valve Reactor Technology— an ingenious circuit design that uses a 12AX7 tube to replicate the output-stage characteristics of class A and class AB tube guitar amps. B

By Art Thompson

With its introduction of the Valvetronix series amps in 2002, Vox upped the ante in the digital-modeling game with its proprietary Valve Reactor Technology— an ingenious circuit design that uses a 12AX7 tube to replicate the output-stage characteristics of class A and class AB tube guitar amps. By cleverly utilizing the two amplifying stages in the 12AX7, Vox designers created a miniature tube power amp, and then elegantly configured it so that when you selected, say, an AC30 model, the VRT circuit would switch into class A operation, and also configure itself for no negative feedback—as per the real amplifier. (If you selected a Fender Twin, the VRT would snap into class AB with negative feedback.) The ultimate benefit of VRT technology is greater realism for the modeled amp sounds, as well as a more dynamic playing feel.

Now, with the introduction of the ToneLab ($449 street) Vox has created a desktop version of its Valvetronix amps, but with significantly upgraded features, including a separate cabinet models section, greater control over the effects (three adjustable parameters instead of two), up to four simultaneous effects, an S/PDIF out, MIDI capability, and editor/ librarian software for enhanced effects editing. (Tech-oriented tweakers can download Vox’s Sound Editor at valvetronix.com or voxamps.co.uk, which allows you to use your PC to edit the ToneLab’s expanded set of parameters).

Holdovers from earlier Valvetronix designs include an easy-to-use knob-based interface and a 12AX7 tube, which is prominently displayed under a Plexiglas bubble. The ToneLab’s aluminum enclosure, which measures approximately 12w" x 8q" x 2q", is anodized in a handsome shade of blue, and it features 3/16"-thick plain aluminum sides. Plastic feet are fitted to protect work surfaces and, unlike some desktop processors, the 5.5 lb-unit is heavy enough to stay put when you’ve got a bunch of cords plugged into it.

The ToneLab’s control panel sports a large LED display, which not only indicates the model and preset names, but also shows the number and type of output tubes used in the real amp (e.g. four EL84s for an AC30, and two 5881s for a Bassman). Cute! The controls are practically self explanatory. Amps, cabinets, and pedals are selected with the chicken-head knobs, and you activate effects types using the buttons located just below the Tap button. The amp models are controlled via the seven knobs at the lower part of the panel, and you tailor the effects via a three–knob system that adjusts different parameters depending on the effect type selected. For example, if you select Tube OD the controls are Drive, Tone, and Level. Switch to Compressor, however, and the same knobs adjust Sensitivity, Attack, and Level.

Sound Lab
The ToneLab could hardly be easier to use, and though the factory presets are a good way to get a quick overview of what this box can do, the real fun begins when you put the ToneLab in Manual mode (by pressing and holding the Bank up/down button for a couple of seconds), which allows you to select a basic amp sound and start building from there. Here’s where you can chuck the manual, too, as all functions are clearly labeled and right at your fingertips. I spent hours just playing with different amp, speaker, and effects combinations, and the results can be startling. As with the Valvetronix amps, the ToneLab’s amp simulations are excellent. The Vox AC15 and AC30 models offer the chime and complexity associated with EL84s, the tweed Fenders are bright and meaty, and even the high-gain Mesa/Boogie, Soldano, and Marshall models respond well to picking dynamics and guitar volume changes.

Whether auditioned through headphones, recorded on a Tascam Pocketstudio 5 digital recorder, or fed into the effects return of a Mesa/Boogie Blue Angel (driving a Dr. Z 2x12 cabinet), the amps sounded rich and balanced. The only exception was the ’68P setting through the Blue Angel, which sounded appreciably duller than the other selections—kind of like a blanket was suddenly thrown over the speakers.

The ToneLab allows you to mix and match cabinet models with any of the amps,

and that adds a lot of versatility to the sounds. For example, you can mate the Black 2x12 model (which replicates the thick mids and glassy top of a Fender Twin) with a Tweed 4x10 cabinet to obtain a more Super Reverb kind of tone, or you can run UK Blues (a model of an early KT66-powered Marshall) into a Vox AC30 cabinet to create something akin to a ’60s-era Bluesbreaker combo. Running small amps into large cabs, such as the AC15 into the UKT75 4x12—or vice versa, by feeding, say, the intense-sounding Recto model into a Tweed 1x12—can yield exciting results. And with 16 amp models and ten cabinet models to choose from, you can obviously spend a lot of time just experimenting.

Of course, sticking with the amps and cabinets would be denying yourself the fun of playing with all the effects. I love the lush chorusing, phasing, and tremolo, and the delays are a total groove—especially the Tape Echo when set for lots of repeats, and Multi Head, which offers some very spacy sounds. The three reverb flavors are also cool, with the Spring setting lending Fender-flavored ambience and dimension to the cleaner amp sounds .

As alluded to earlier,

the three adjustable parameters for each effect (the original Valvetronix amps had two variable parameters for the pedal, modulation, and delay effects, and only one for the reverbs) greatly enhances the ToneLab’s utility. The extra control allows the Tube OD and Fat OD models to sound truer to the Ibanez Tube Screamer and Pro Co Rat boxes they’re based on, while the Octave pedal can yield much wilder effects courtesy of its separate high and low octave adjustments. Likewise, it’s nice to have Time, Mix, and Feedback controls for the delays (especially if you love hearing repeats cascade into oblivion), and being able to vary the Auto Wah’s Attack (response speed), Sensitivity (input level required to open the filter), and Polarity (upward or downward sweep direction) is icing on the cake for this cool effect. And, if you use the expression-pedal-equipped VC 12 foot controller ($279 street), you’ll appreciate being able to adjust the Vox Wah’s open- and closed-pedal settings—it’s like virtually reaching in and resetting the little plastic gear strip that turns the pot on the real pedal.

The Acoustic setting also benefits from having Bass, Treble, and Body controls—the latter of which boosts subharmonic frequencies to mimic the “boom” of a big-bodied flat-top. I wouldn’t call the sound with a Les Paul plugged into the ToneLab exactly “acoustic,” but it certainly has enough of that airy vibe for demos and song sketches.

Lab Results
The ToneLab is a wickedly cool desktop modeling amp that could easily be pressed into gig service with the addition of a power amp (stereo, if you like) and speakers. The device scores major points for ease of use, tonal authenticity, and excellent dynamic response across a broad spectrum of clean and overdriven sounds. Factor in its relatively low sticker price (two boutique stompboxes would cost you more), and the ToneLab deserves nothing less than an Editors’ Pick Award.