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VOX valve reactor

PostPosted: Sat Mar 12, 2011 3:08 pm
by Vincent
How many out there play through Valve reactor amps??

Personally I found these louder than the previous models, but am not entirely sure of the valve reactor theory. Does it give 'valve like' sounds or tones?? The valve is in the power amp section

Re: VOX valve reactor

PostPosted: Sat Mar 12, 2011 6:50 pm
by roger bayliss
I had the AD120VT for a while and it sounded very good. Not as warm as an all valve but better than a transistor amp

Re: VOX valve reactor

PostPosted: Sat Mar 12, 2011 10:05 pm
by Didier
Vincent wrote:The valve is in the power amp section

The valve is in the preamp section. There is no valve in the power amp section.

Didier

Re: VOX valve reactor

PostPosted: Sat Mar 12, 2011 10:16 pm
by ecca
I thought it sounded odd to have a valve in the power section, I couldn't imagine how they'd do it.

Re: VOX valve reactor

PostPosted: Sun Mar 13, 2011 3:19 am
by panchodiaz
The valve is a 12AX7, a preamp valve but used in the power section. It amplifies the signal to 1 w and later, that signal goes into the Valve Reactor circuitry and it is amplified to 15, 30 or 60 watt. At least in my Valvetronix 120AD

Re: VOX valve reactor

PostPosted: Sun Mar 13, 2011 9:12 am
by RUSSET
Pancho is right. I had an AD30VT for a while, & if you read the Vox manuals, the 12AX7 valve is actually in the power amp section just prior to the actual solid state power amp. It is supposed to give the feel of an AC30 type gain as you turn up the output & it begins to drive. The pre-amp section is all digital solid state including all the amp modelling & effects sections.
It was quite a nice amp with some very good tones, especially considering the price you paid. It is not quite a Vox valve toned amp, but good value for what you get, especially with all the variety of amp models. I only sold it on because I found the Fender Superchamp XD, which has the digital modelling & effects, & has a valve pre-amp & power amp section.
Tony.

Re: VOX valve reactor

PostPosted: Sun Mar 13, 2011 9:42 am
by Didier
panchodiaz wrote:The valve is a 12AX7, a preamp valve but used in the power section. It amplifies the signal to 1 w and later, that signal goes into the Valve Reactor circuitry and it is amplified to 15, 30 or 60 watt. At least in my Valvetronix 120AD

Which confirms that the amp power doesn't come from the valve...

Didier

Re: VOX valve reactor

PostPosted: Sun Mar 13, 2011 12:56 pm
by panchodiaz
Just the opposite, Didier. Copied from the Vox website:

VR Valve Reactor
Originally designed for the critically acclaimed Valvetronix modelling amplifiers, the Valve Reactor circuit places a 12AX7 vacuum tube (or “valve”) into the power stage. Known as a dual-triode tube, the 12AX7 is actually two tubes in one. Our engineers have configured this tube to act as a small power amplifier...


http://www.voxamps.com/valvereactor/

Re: VOX valve reactor

PostPosted: Sun Mar 13, 2011 6:01 pm
by Didier
panchodiaz wrote:Just the opposite, Didier. Copied from the Vox website:

VR Valve Reactor
Originally designed for the critically acclaimed Valvetronix modelling amplifiers, the Valve Reactor circuit places a 12AX7 vacuum tube (or “valve”) into the power stage. Known as a dual-triode tube, the 12AX7 is actually two tubes in one. Our engineers have configured this tube to act as a small power amplifier...


http://www.voxamps.com/valvereactor/

You'll never get 15W or more from a 12AX7, even if the valve is in the first stage of the amp section, the effective output power doesn't come from it, but from an IC power section...
Have a look here, and you'll have confirmation : http://www.valvetronix.net/docs/AD15_30 ... manual.pdf

Didier

Re: VOX valve reactor

PostPosted: Sun Mar 13, 2011 6:26 pm
by ecca
You're right Didier.
The circuit diagram is crystal clear.
The power amp is an LM3886.