The E.Q network operates at the extremities of the audio bandwidth. Upper frequencies can easily be boosted with the ‘ air ‘ selector without sounding harsh or false. This happens before any active circuitry so noise is kept to a minimum. Similarly, frequencies in the lower spectrum are easily contoured by the ‘ deep ‘ control which operates from the 300hz region downwards. The EQ network can be hard bypassed and is also interactive with the ‘ pad ‘ switch to attain an even wider range of colours and textures, many of which are unavailable on other units.

Thorax’s compressor stage uses a unique Sebatron-designed optically driven gain reduction circuit that gives fast, tight control over the dynamics of a signal with a minimum of colouration. It has controls for Threshold, Ratio, Attack and Release, with the attack/release factor switchable over three ranges. Makeup gain is provided by a valve stage with a three position Drive control.

This audio path is complemented by a large, easy to read VU meter that can be switched to indicate preamp or main output level or compressor gain reduction.