Ultra-Compact 4-Channel Stereo Headphone Amplifier. The AMP800 features 4 totally independent stereo high-power amplifier sections, each with dual outputs. You can use the Phones Level control plus the accurate 6-digit LED output meter per channel for easy level monitoring. There are 2 balanced Stereo Main Inputs with independent Level and Balance controls for individual mixes, selectable for all 4 of the headphone amplifiers. If you need to accommodate more than 8 listeners, the convenient Link Out A enables cascading additional AMP800s.