Valve Reactor technology was first used on the VOX AD60VT & AD120VT Valvetronix
amps.
Since conventional modeling effects for line recording are not used directly with a
speaker, they do not include a power amp circuit, output transformer, or speaker. In other
words, they only have a preamp circuit.
A real valve amp sound, however, is produced not just by the preamp, but also by the tone
and distortion of the power amp, and by the constant changes in impedance that are created
by the power amp driving the speakers. The AD15VT, AD30VT, AD50VT & AD100VT
contain an actual low-wattage valve power amp circuit, a virtual output transformer (patent
applied for) that uses solid-state components to simulate an output transformer, and a
dummy speaker circuit that simulates the varying impedance of a real speaker. This
means that although it’s low-power, the power amps used in both the AD15VT, AD30VT,
AD50VT & AD100VT have the same circuit structure of an actual all-valve (tube) amp.
While much of the tone creation and shaping carried out is done in the digital
domain, the Valve Reactor power amp is 100% analogue. The resulting journey your guitar’s
signal takes through the analogue world of the power stage plays a major role in providing
the all-important feel and tone of the original amps we modelled.
The Valve Reactor power stage is, to all intents and purposes, a bona fide valve (tube)
push-pull power amplifier, but in miniature. It utilizes a 12AX7 (ECC83) valve (a dual triode
device — meaning “two valves in one”) and is equipped with an output transformer,
just like a “real” valve amp.
The power amp output signal is designed to “read” the constantly changing impedance
curve of the dummy speaker circuit system and feed this information back to the virtual
output transformer — just like an all valve amplifier does. This information permits the
behavior of the valve stage to vary with the speaker load (impedance), which is another
important part of “real world” valve tone.
Apart from the vital valve tone this ingenious power amp design provides, it also
allows us to replicate various “circuit characteristics” that are unique to the all-valve
power stages of the amps we’ve modelled. These “characteristics” include: Class A or
Class AB operation, Presence and Resonance (low end) control circuitry (both found in
the negative feedback circuit that some, but not all, valve power amps have) and power
output. Being able to match such vital characteristics helps ensure that each and every
one of our models is as tonally authentic as possible — as opposed to the usual “close
but no cigar” norm of digital modeling. And just so you know, this patented in USA power
amp technology is unique to VOX Valvetronix.
Размещение рекламы