General Overview

The two Telfunken V672/2 amplifiers are mounted in an aluminum rackmount case provided by Sescom and can be seen below.  The amplifiers are configured as Microphone preamplifiers with a single input and two outputs.  The inputs for both amplifiers use a Neutrik combo connector providing both XLR and 1/4" TRS inputs.  The outputs are available as XLR and 1/4" TRS from the two outputs that this Telefunken module provide.   Phantom power and gain for each channel are controllable from the swtich and potentiometer on the front of the rack chassis.  The modules are removable from the chassis for easy service-ability and slide on Vector rails for easy mounting.

The Power Supply for this unit is rackmounted separately and provides the transformers, full wave rectifiers, and pre-regulation to the unit via a 4 Pin XLR connector.  The on-board regulator takes the +32V from the pre-regulator and regulates it down to +24V to supply the two amplifiers.  Additionally, +48V phantom power is derived from the separate +52V pre-regulated input.  The phantom power is fully regulated using a separate power transformer, it is not achieved using a voltage doubler or tripler circuit.  The dual regulation methodology used allows for remote mounting of the power supply and provides extra filtering.  All of the regulators are adjustable avoiding the noisier fixed regulator chips.