Musical Instrument Amplifier User Manual

Welcome to VOX

Many thanks for adding the VOX AC30VR/AC15VR amplifier to your sonic arsenal.

It was designed by our UK based VOX engineering team and built by our state of the art, vertically integrated manufacturing facility

and we’re sure it’ll give you countless hours of great guitar tones that will feel as good as they sound! To insure a long and happy

relationship with your amplifier, please read this manual at least once, and (as they say), “use the product as directed.” Keep the

manual for future reference after you’ve read it.

WHAT IS VR?

The VR series of amplifiers are designed, as to what we

believe are the next generation of “hybrid” guitar amplifiers.

What does HYBRID mean, you may ask? Well, basically

“hybrid” means that it utilizes a mixture of technologies—in

this case those technologies are Tube and Solid State.

The Preamp stages consist of discrete transistors for sound

generation, and integrated circuits (op-amps) to do signal

management that would not be done effectively with transis-

tors alone—i.e. channel switching, etc.

The Power amp stage uses a 12AX7 vacuum tube (or valve,

depending where you live in the world) in a configuration that

we at VOX call Valve Reactor.

The patented Valve Reactor power amp technology is used in

all Valvetronix products. It was originally designed for the

award winning VOX Valvetronix modelling guitar amplifier

range, and now we have taken that same technology and fur-

ther revised it into the format that is built into your AC30VR/

AC15VR amplifier.

HOW DOES IT WORK?

It basically works by having each half of the 12AX7 (the

12AX7 tube is actually two identical tubes in one glass tube

a.k.a. dual triode) and configuring it to work as a small tube

power amplifier. This circuit provides all the tonality and feel of

an all-tube power amp. Obviously this “small” power amp

would not be very loud if it was connected directly to a loud-

speaker—therefore the tube circuit is connected to a larger,

completely transparent solid-state power amplifier, that is run

very cleanly so that it does not add its own colouration to the

tube signal.

This power output amplifier also has some special circuits that

feed the loudspeaker impedance information back to the tube

power amplifier in order to give it the loose sound & feel that

an all-tube amp does.

SO WHAT DOES THIS MEAN?

We think that the VOX VR amplifier range brings you superb

tone (vintage & modern) that includes the high harmonic con-

tent and compression that goes all the way back to the original

VOX AC15 & 30 amplifiers that were created more than 50

years ago, and are still revered to this day.