In the Valve Reactor power amplifier, a 12AX7 dual-triode tube is connected directly to an output transformer and produces 0.4 Watts. 12AX7s are typically used as preamp tubes. The amp’s designers had to develop a way to raise that level to one which could actually drive speakers to normal volume levels while maintaining the integrity of the tube-amp sound and feel. They accomplished this by creating a circuit of proprietary design dubbed the VOX VariAmp Power Circuit. The output transformer is connected to this VariAmp Power Circuit which uses Constant Current design and Reactive Feedback technology. The VariAmp Power Circuit cannot be overdriven, is totally transparent and can be configured to be 1, 15, 30 or 60 Watts. 

Another unique aspect of VOX’s Valve Reactor is its ability to reproduce various circuit characteristics of the all-tube power stages of the amplifiers being modeled. The Valve Reactor has the ability to automatically switch between Class “A” and Class “AB” depending on the amplifier it is modeling. For example, all of the VOX models in Valvetronix amps employ Class “A” circuitry. When the player selects a VOX model, the Valve Reactor automatically switches to Class “A.” If the player selects an amp model that has a Class “AB” power amp, the Valvetronix amp instantly switch to that class.

THE FRONT END, WHERE IT ALL STARTS  

The preamp section of the Valvetronix amplifiers employs Korg’s proprietary REMS™ (Resonant structure and Electronic circuit Modeling System) technology. The critically acclaimed REMS has the ability to accurately reproduce the complex circuitry within the modeled amplifier’s signal path and re-create the tonality originally created in that amplifier’s circuitry. For example, REMS replicates the unique tone-stack network of each of the Valvetronix’ 16 amplifier models and, as a result, the Valvetronix Tone Controls operate and interact as they do in the amplifiers being modeled.

AD60VTX (60 Watts, 1 x 12") and the AD120VTX (2 x 60 Watts, 2 x 12")

Two models comprise the VOX Valvetronix Series of amplifiers: the AD60VTX (60 Watts, 1 x 12") and the AD120VTX (2 x 60 Watts, 2 x 12"). Both feature the ability to replicate 16 of the most sought after amplifiers such as a Tweed 1 x 12, Tweed 4 x 12, AC15, AC30TB, US High Gain, Boutique OD/Clean as well as a host of other popular UK amplifier models. The AD60VTX and AD120VTX also feature 32 programs (4 channels x 8 banks), 21 effect types (10 Pedal Types, 5 Modulation, 3 Delay, 3 Reverb) plus noise reduction, an FX loop, external speaker out, plus a power select switch. In addition, both amplifiers have a built-in Korg Auto-chromatic tuner and come with custom-designed Neodimium (Neo Dog) Celestion 12" speakers (1x12" on the AD60VTX, 2 x 12" on the AD120VTX).

Click the panel for an even closer view (more detail)

THE SIGNAL PATH

Signal path is another critical factor in the design of a modeling amp if it is going to be capable of accurately modeling the sound, tone and feel of desirable classic and modern amplifiers and effects. When laying out the Top and Rear panels of the Valvetronix AD60VTX and AD120VTX amplifiers, VOX looked at how guitarists typically set up their rig and laid out the Valvetronix’ signal path exactly like the real deal.

BUILT-IN PEDAL EFFECTS

The effects in Valvetronix amps are not an afterthought. Each is a carefully designed model of one of a variety of classic and popular effects. The 10 different “gotta have” pedals include Compressor, Acoustic Simulation, VOX Wah, Auto Wah, U-Vibe, Octave Divider, Treble Boost, Tube Overdrive, Fat Overdrive and Fuzz. The continuous controller pedal on the optional VC-4 Foot Controller can be used to control both the U-Vibe and VOX Wah models as they would be on the originals.  As pedals, they appear before the preamp models so they can drive the preamp in the same way they do in a traditional rig.  For example you can choose the Treble Booster to overdrive the input of a VOX AC30 for a sweet massively compressed tone made famous by one of VOX’s most illustrious users.

The most important factor in the design and construction of these Valvetronix amplifiers is the sound and feel. Valvetronix is a tube amplifier and feels like one. The tone is fat, round and punchy.

See your local VOX dealer and take a test drive. Let your ears and fingers take a ride.