The 520D from Aphex is an "Aural Exciter" plug-in module that fits the TOA 900, Raymer 9000 and Peavey MA Series power amplifiers. The processor provides many benefits including greatly improved presence and intelligibility without altering any other part of the audio system.
The "Aural Exciter" is a dynamic process that recreates missing harmonic material lost to general degradation of the audio signal as it passes through any audio system and adds it back in the form of a very small cue signal. Because the enhancement signal is so small, it adds little power to the audio signal.
The module installs in a single module space on the rear of the amplifier and takes its power from the amplifier. Bass boost for 0, +6 or +12dB of boost is jumper selectable. The 520D is a single channel input card. Its RCA type phono jack takes any line level unbalanced input. The operating level may be selected for -10dBV or +4dBm.