Vox makes no secret that it’s Valvetronix line of amps incorporates a 12AX7 tube. Tube amps have a well earned reputation for excellent tone and most of the classic guitar sounds we are all familiar with were done with tube amps including other amps made by Vox. Unfortunately tube amps also have their drawbacks such as weight and cost so the Valvetronix line of amps fills a good niche. The latest evolution of the Valvetronix line is the Vox Valvetronix VT40+
Vox has determined that adding a tube in the output section produces the best tone as opposed to adding it in the preamp section. In the preamp Vox has a well regarded amp modeling circuit so adding the tube in the output makes perfect sense.
This graphic below describes how the Vox Valvetronix amps work.
In the Vox Valvetronix VT40+ the signal enters the amplifier it first goes through the pedal effect section. The Valvetronix includes a good selection of pedal effects such as multiple overdrives, treble booster, wah and many more.
After the pedal circuit the signal goes into the preamp This is Vox’s great sounding amp modeling section. The VT40 includes 33 amp models that range from clean to modern high gain. No doubt there is something in there for everyone. The preamp also includes all the classic tone shaping knobs you would expect on an amp. These controls include Gain, Volume, Treble, Middle, Bass and Master Volume.
After the preamp the signal goes into the modulation/delay effects. this section is the equivalent of an effects loop in that it’s after the preamp and before the power amp. The effects included here are flanger, delay, chorus and more and then on to the reverb section. Between the included pedal effects and post-preamp effects, Vox in ensuring you need nothing more than their amp!
After the reverb the signal gets to the power amp. The power amp is the part that really separates the Vox Valvetronix VT40+ from other modeling amps in it’s price range. Vox has gone the extra mile to make the output section more responsive than your typical modeling amp.
The 12AX7 tube used in the Valvetronix is actually two tubes in one glass enclosure. Most tube amps use 12AX7s in the preamp and are usually cascaded, meaning the signal goes in the first section of the tube then the next. In the Valvetronix the two section of the 12AX7 is used in the output section to create a true push/pull amplifier. The output section is really a clever combination of old school vacuum tube technology mixed with modern modeling technology.
This graphic has a more complete explanation of the output section is you are interested.
If you are looking for a high quality amp that offers up just about any amp or effect for a reasonable cost the Vox Valvetronix VT40+ is definitely one to look at.