The AN-001T is a plug-in module of 2-channel ambient noise detector designed for use with the 9000 series amplifiers. It automatically adjusts the output volume in response to the change of ambient noise level. The AN-001T can handle input signals from microphone level (-60 dB) to line level (-10 dB) by controlling the gain in 9 steps. Phantom power (+24 V) can be supplied for condenser microphone use.