Boss MG 80 / Vox Tone Lab

Model: BOSS MG 80 / Vox Valvetronix Tone Lab Modelling Valve Guitar Preamp / Used

80 watt, solid state

2 x 5″ speakers

1/4″ inputs high/low 

Gain, Volume, Master Volume, Bass (w/Pull Warp control), Middle, Treble, Presence

1/4″ Headphone Jack

optional 1/4″ output for ext 8 ohm

Vox Tone Lab:

When I first checked out the presets using both a Strat and a Les Paul, I got the impression that they were slightly over-bright, but a little editing definitely helped. After some of the other modelling preamps, the Tone Lab seems slightly strange at first, until you realise that it’s because it behaves more like a real amp and doesn’t have the same instant-gratification, mega-produced sounds that some units try to deliver. Not that you can’t dial in some compression, delay and reverb to get a very produced sound if that’s what you’re after, but if you strip all that away and listen to the amp models, they have a welcome degree of reality and musicality about them. They certainly capture the elusive feel and dynamic response of a real amp, and if at some settings the sound seems a little gritty and edgy, that’s probably because a real amp would too under the same conditions!

Vox Tonelab Amp/Cabs
The Valvetronix Tone Lab lets you choose from 16 amps and 11 cabs, directly from the front-panel chicken-head rotary switches.
After a little tweaking, I was soon able to get most of the right sounds, or at least sounds I perceived to be right, given that guitar sounds are such subjective things. Doing a direct comparison with my Pod XT, I found that the sound had more ring to it and more definition at the starts of notes. The sounds I’ve always found hard to replicate are those powerful but almost clean sounds, with a hint of compression, or those dirty ’60s R&B chords (I use R&B in its original and correct context here!). I have to say that the Tone Lab really excels in this area, and while I found it marginally easier to get the types of overdriven sounds I liked from my Pod XT, the Tone Lab was a clear winner when it came to country guitars, clean Floyd sounds, Dire Straits-like tones, vintage Stones — or just plain old rhythm guitar. It was almost as though the guitar itself had more life and that the tonality was enhanced by the preamp rather than being buried by it. Interestingly, one of the nicest quasi-clean sounds I got was by using the Recto amp model (with the gain backed right off) teamed with a British 4×12 cab, compressed just a hint — very ‘All Along The Watchtower’!

When it comes to dirtier sounds, it’s hard to choose, because one unit might win out in some areas, while its rivals pull ahead in others. I think it fair to say that the Tone Lab is more amp-like, though, and its sounds cut through better, even though the Pod XT makes it easier to recreate many of the overdrive sounds you hear on records. It’s all a bit unsettling, because I really like my Pod XT, but during the course of this review I got some great touch-responsive sounds using the Tone Lab that I couldn’t quite match any other way.


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BOSS MG80 / Vox Valvetronix Modelling Valve Guitar Preamp LAB

MG 80:

80 watt, solid state / 2 x 5″ speakers / 1/4″ inputs high/low / Gain, Volume, Master Volume, Bass (w/Pull Warp control), Middle, Treble, Presence / 1/4″ Headphone Jack / optional 1/4″ output for ext 8 ohm

Tone Lab:

The Vox Valvetronix Tone Lab is a spin-off from Vox’s AD60/120VT modelling amplifiers, which take the approach of combining digital modelling and signal processing with both solid-state and analogue amplification stages, rather than trying to emulate absolutely everything digitally. Conceptually, the Valvetronix Tone Lab fits into the same camp as products like the Line 6 Pod (amp/speaker modelling plus effects) and can be used either for DI recording or to feed an amplifier for live performance. However, whereas the Pod takes the all-digital approach, the Tone Lab includes a miniature power-amp stage based around a 12AX7/ECC83 dual-triode tube, where some clever ‘pseudo-transformer’ circuitry has been used to make this influence the sound much as a real power stage would. Such innovative technology has to be given a fancy name, and in this case it is the Vox Valve Reactor.   Much of the effort has gone into recreating the effect of an output transformer without actually having one, an important factor given that the output transformer and the way it interacts with the loudspeaker load forms a crucial part of the tube-amp sound. The Presence control on those amps that feature one also relies on the output transformer — rather than simply being EQ as you might imagine, Presence controls adjust the amount of negative feedback in the power amp section from the output side of the transformer, which means that the effect is actually quite complex. Furthermore, this miniature power stage automatically switches between Class A and Class AB depending on the amp model selected, and the output tubes of the original amp are shown in the display window for whatever model is active. Vox AC15s and AC30s used Class-A circuits, whereas the majority of Marshall and Fender designs, other than very low-power models such as the Fender Champ, have Class-AB push-pull output stages. Not only does the correct choice of power amp characteristic affect the sound, but it also changes the way the guitar feels to the player, which is a vitally important element of any guitar amplification system, and one that probably makes no sense at all to keyboard players!