The MC624 is similar to the monitor section of a mixing desk: it lets you select one out of six stereo audio sources, adjust the level and route it to one of four monitor outputs.

The TS500 is an analog processor that recreates the sonic imprint of vintage tape recorders. It provides the roundness, the punch, the compression and the saturation of magnetic tape.

The DI503J is a triple mode Direct Box for instrument and a Re-Amp unit for the '500' format of API*.

The PAD500 is a dual balanced line attenuator. It is used after a mic preamp or any effect that you want to drive hot without clipping your converters.

The REM624 is a remote control unit for the MC624 Monitor Controler.

It offers the same contols as the central unit (except headphones volume).