power amplifier: Simple,reliable design incorporates many popular features. Housed in a rugged, all-steel 2U chassis (3U in the XLS5000). Effcient forced-air fans prevent excessive thermal buildup. Electronically balanced XLR inputs. Touch -proof binding post and Speakon outputs. Features precision detented level controls , power switch , power LED, and six LEDswhich indicate signal , clip, fault for each channel. Specifications Sensitivity (volts RMS) for full rated power at 4 ohms 1.25 Frequency Response (at 1 watt, 22 Hz - 20 kHz) +0 dB, 1 dB Signal to Noise Ratio below rated power (20 Hz to 20 kHz, inputs terminated) A-weighted, below rated power No weighting, below rated power > 100 dB > 95 dB Total Harmonic Distortion (THD) at 1 full bandwidth power, from 20 Hz to 1 kHz < 0.5% Intermodulation Distortion (IMD) 60 Hz and 7kHz at 4:1, from full rated output to 30 dB < 0.3% Damping Factor (8 ohm): 10 Hz to 400 Hz > 200 Crosstalk (below rated power) at 1 kHz at 20 kHz 75 dB 50 dB Input Impedance (nominal) (balanced,unbalanced) 20 kilohms, 10 kilohms Load impedance Stereo Bridge mono 4-8 ohms 8 ohms AC Line Voltage and Frequency Configurations Available (± 10%) 120 VAC 60 Hz 100 VAC 50/60 Hz 220 VAC 50 Hz 230-240 VAC 50 Hz Ventilation Flow-through ventilation from front to back Cooling Internal heat sinks with forced-air cooling Air Volume Requirements (per minute per unit) 80.15 ft3 (2.27 m3)