Power Amplifiers

This graph shows that the LX-7's left amplifier channel, with two channels driving 8-ohm loads, reaches 0.1% distortion at 293.2 watts and 1% distortion at 322.5 watts. Into 4 ohms, the amplifier reaches 0.1% distortion at 245.3 watts and 1% distortion at 286.8 watts. An input level of 102.4 millivolts was required to produce an output of 2.83 volts into an 8-ohm load, indicating an overall gain of 28.83 decibels using the RCA input. When using the XLR input, a level of 205.0 mV was required to produce an output of 2.83 volts into an 8-ohm load, indicating an overall gain of 22.80 dB. With six channels driven into 8-ohm loads, the amp reaches 0.1% distortion at 199.5 watts and 1% distortion at 228.6 watts.

The amplifier's frequency response measures -0.05 dB at 20 hertz and -0.03 dB at 20 kilohertz. Looking at a broader bandwidth, the response measures -0.16 dB at 10 Hz and -0.34 dB at 50 kHz. THD+N from the amplifier was less than 0.014% 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 0.009%. Crosstalk at 1 kHz driving 2.83 volts into an 8-ohm load was -100.45 dB left to right and -104.16 dB right to left using the RCA input and -105.41 dB left to right and -106.17 dB right to left using the XLR input. The signal-to-noise ratio with 2.83 volts driving an 8-ohm load from 10 Hz to 24 kHz with "A" weighting was -102.05 dBrA using the RCA input and -109.94 using the XLR input.—AJ