- Published on 15 December 2008
The XPA-2 is a class A/B design amplifier. Class A amplifiers are desirable by audiophiles because of their linearity but their drawback is that they are inefficient. Even when there is no audio signal sent to them they are still drawing current in almost the same way as when a full signal is present. This makes them very costly because they require massive power supplies and enormous heatsinks to keep them cool while they dissipate heat. Class B amplifiers are a much more efficient design because they amplify only half of the waveform, but as a result have very high levels of distortion which makes them unsuitable for audio uses. Class A/B amplifier offers the trade off solution in that they take advantage of the efficiency of a class B amplifier but also reduce the amounts of distortion in the output.
The XPA-2 is bulky and is also rather heavy at 75 pounds. It just barely fits in my audio rack, and it's best moved with two people. A lot of its weight is attributed to its hefty heat sink as well as the massive singular power supply that drives both channels. The XPA-2 delivers 250 watts RMS per channel at 8 ohms and will drive 4 ohm speakers at up to 500 watts. if you really need a lot of power, you can max it out at 1000 watts RMS in bridged mode.
The amplifier has good build quality and is all black with silver edges on the right and left sides of the front panel. The front also features a soft blue LED meter that fluctuates with activity and will turn red if the signal starts clipping. You can turn off this light using a switch on the back panel. On the back panel there are connections for balanced and unbalanced input and there are printed labels that guide you when bridging the amplifier.