Solid State Logic X-Rack VHD Mic Amp Module

The X-Rack VHD Mic Amp Module from Solid State Logic is a single channel microphone/line preamp and part of the X-Rack modular system. It includes a unique Variable Harmonic Drive (VHD) system that can blend in various amounts of 2nd or 3rd harmonic distortion to the input signal.

At relatively low input gain settings the preamp delivers ultra-clean recordings. Increasing the input gain and adjusting the VHD control injects anything from '50s valve-style overdrive, through to hard-edged '70s transistor-style grit, or any blend of the two. In addition to the drive circuitry, the module provides high- and low-pass filters, a trim control and 20dB pad.

The SSL 'Listen Mic' Compressor was, throughout the 1980's, the secret weapon in many producers' sonic arsenal of recording techniques. Originally designed to prevent overloading the return feed from a studio communications microphone, its fixed attack and release curves were eminently suitable for use on ambient drum microphones.

The original circuit has been added into the XRack VHD Mic Amp Module, enhanced with the addition of a front panel threshold adjustment. The circuit follows after the Trim and Filter stages enabling either microphone or line level signals to be trimmed and shaped before benefiting from the sonic possibilities provided by this compressor.