The BalancedReceiver circuit adds balanced inputs to your power amplifier. Based on Burr Brown INA134 IC, it adds almost no distortion and/or noise. The supply voltage is derived on the circuit from the rail supply of the poweramp (anything between dual 18-60V should do). More information and test results can be found in the Mosfet amplifier project page.

Note that currently revision 2 is shipping, which is a major redesign with additional input buffers before the differential receiver and output buffers with independent volume control. Revision 1 does not have the additional buffers, and is therefore cheaper but less flexible. More information about the differences and the complete lists of components can be found in the mounting instructions (see Downloads).