I recently obtained a pair of RT55 speakers. We tested them with a Peavey M-2600 power amp which supplies 75W into 8 ohms. We then connected them to an Optimus AV amp which supplies similar wattage. When you set the volume at 12 o'clock or so on either amp, the power drops out. I am assuming this is the amps internal protection circuit kicking in. Both amps are normally used to run a pair of 8 ohm PA speakers and we haven't had this issue before and we have run them well past 12 o'clock. Any ideas on why this is happening?