Max balanced input: +27,5dBuMax unbalanced send level: +22dBuMax return input level: +22dBReturn gain: 0-20dBReturn input impedance: 1MohmMax balanced output: +27,5dBuSend frequency response: 10-100kHz +/-0,1dBSend THD+N @ 1kHz: less than 0,001%Return frequency response: 10-100kHz -0,2dB (at 10Hz)Return THD+N @ 1kHz: less than 0,003%Rear panel has four XLR inputs and four XLR outputs.