| The circuitry for the AD100VTH was mounted on two circuit boards. The upper circuit board contained all the REMS (Resonant Structure and Electronic Circuit Modeling System) preamp circuitry. 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 was held in place by the control nuts. There are no consumer serviceable parts in the preamp circuitry.
The lower board contained the power supply and Valve Reactor power amp circuitry. 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 100 watt RMS solid state portion of the Valve Reactor circuit was housed on a single, integrated chip that is mounted to a fan cooled finned aluminum heat sink. The 12AX7 tube is the only consumer serviceable part in the power supply and output amp circuitry.
Changing the 12AX7 Tube in the AD100VTH
Unplug the amp from the wall. Make sure that the tube has cooled before proceeding. The 12AX7 may be accessed through a hole in the bottom of the head cabinet.
|
