The 12AX7 tube for the Valve Reactor power amp was located toward the rear of the lower circuit board in the area under the rotary 'Amp' model switch. The lower board contained the power supply and Valve Reactor power amp circuitry. There are no consumer serviceable parts in the preamp circuitry. The upper circuit was held in place by the control nuts. This included the volume, treble, and bass controls along with the digital processors for effects such as reverb, echo, chorus, flange, tremolo and amp modeling. The upper circuit board was suspended below the control panel and contained all of the REMS (Resonant Structure and Electronic Circuit Modeling System) preamp circuitry. The circuitry for the AD15VT was mounted on two circuit boards. This modification simplified the power amplifier circuit and contributed to the cost savings that allowed Vox to introduce the 'AD Chrome Series' amps at such an affordable price. The new VR power amp circuit in the chrome grill AD amps eliminated the output transformer, replacing it with a coupling capacitor. In 2002 literature promoting the original 'blue grill' Valvetronix amps, Vox explained that the interaction between the 12AX7 power tube and the tiny audio output transformer combined to allow these models to simulate the tone of an all tube power amp.Ī revised version of the VR power amp circuit was used in the AD Chrome amps. The output from this circuit was used to drive a tonally transparent solid state power amp to boost the RMS output to performance levels. The original VR circuit designed for the Valvetronix 'blue grill' amplifiers coupled a 12AX7 with a small audio output transformer to make a one watt power tube amplifier circuit. The AD Chrome series used the second generation version of the 'VR' or Valve Reactor power amp circuit. Valvetronix amp series offered by Vox from 2004 to 2008. The AD15VT was the entry level model in the 'AD Chrome' No use on online auctions, eBay or Reverb. © 1996 - 2022 The Vox Showroom, all rights reserved.

Vox Valvetronix Ad15vt Schematic