Power Amplifiers

This graph shows that the CX-7's left amplifier channel, with two channels driving 8-ohm loads, reaches 0.1% distortion at 198.3 watts and 1% distortion at 220.8 watts. Into 4 ohms, the amplifier reaches 0.1% distortion at 340.5 watts and 1% distortion at 375.9 watts. An input level of 101.8 millivolts was required to produce an output of 2.83 volts into an 8-ohm load, indicating an overall gain of 28.88 decibels using the RCA input. When using the XLR input, a level of 202.5 mV was required to produce an output of 2.83 volts into an 8-ohm load, indicating an overall gain of 22.91 dB. With all channels driven into 8-ohm loads, the amp reaches 0.1% distortion at 182.7 watts and 1% distortion at 202.0 watts.

The amplifier's frequency response measures –0.03 dB at 20 hertz and –0.02 dB at 20 kilohertz. Looking at a broader bandwidth, the response measures –0.10 dB at 10 Hz and –0.22 dB at 50 kHz. THD+N from the amplifier was less than 0.007% at 1 kHz when driving 2.83 volts into an 8-ohm load using the RCA input. When using the XLR input under the same conditions, THD+N was less than 0.006%. Crosstalk at 1 kHz driving 2.83 volts into an 8-ohm load was –110.79 dB left to right and –111.75 dB right to left using the RCA inputs and –113.60 dB left to right and –110.10 dB right to left using the XLR inputs. The signal-to-noise ratio with 2.83 volts driving an 8-ohm load from 10 Hz to 24 kHz with "A" weighting was –111.92 dBrA using the RCA input and –115.73 using the XLR input.—MJP