My Hafler P500's are also much more potent than these at 1400W+ RMS into 4 ohms, running in mono, not BRIDGED using the now non existant mono stereo switch, it's taken out when AVA rebuilds into sonic masterpieces. New high speed MOSFETS old Hitachis taken out, new MOSFETS from Exicon. I use AVA phase inverters, to monosize the outputs across the 2 hots...mo watts mo' watts 3X or more over standard operation. Bridgeing also causes other distortions, the phase inverters do not...