The D8120 is professional amplifier holding 8-channels Class D switching power supply, impedance of 4 Ohm, power in 250 Watt and 120 Watt. D1660 is a 16-channel amplifier, power of 60 Watt 4 Ohm impedance. Practically speaking, they are simple and easy to install, and can offer a perfect solution for multi-zone. All input and output ports use the Phoenix interface to balance the input signal. Each channel has an independent volume knob and a switch which can select stereo / bridge to avoid signal interference when assigning input signals. Built-in secure system, when the protection light glows, enters protection mode: preventing short circuit, overheating, overload and limiting the signal output.