500 Series Microphone Preamplifier
Mic Preamp with 65dB of gain
Front and Back Panel Mic Input Access
Line/Instrument Preamp with 50dB of gain
Front and Back Panel Line/Instrument Input
LED VU meter for monitoring output level
20dB pad switch, applies to mic/line/instrument
48v Phantom switchable power
Traditional API fully discrete circuit design
Uses the famous API 2520 Op-amp
I never used this piece of gear. It does fit into a 500 series rack though.