API 3124+ 4-Channel Mic Preamp

API's 3124+ is a 1U rackmount unit with 4 horizontal 312 preamps with additional direct input for guitar/bass/keyboard. This is the classic API console mic pre circuit with 2520 discrete op-amp and custom output transformer from the 512c.

Front panel controls include variable gain, polarity inversion, -20dB pad, +48V phantom power toggle, and a mic/DI switch.

Older 3124 (no +) only had rear-panel phantom power switching and no polarity inversion.