Summary: Would not purchase one. They do not last long and cannot be repaired except through Yamaha. The problem is, if the device detects a problem, it "locks down", even if the problem is corrected. There is no way to "unlock" the device, it will remain in lock down mode until it is sent to Yamaha for repair. You can verify my statement by looking in the manual under troubleshooting. I only ran one set of 8 Ohm speakers on this unit, nothing more, and only at half power.