I have an old Sumo Nine, Pure Class A unit, that has never been turned off... except. I took it out of the system for about 4 months while I used Abletec Mono amps (Class D)... My Electric bill went down about $20 a month!... Now they are both in and I'm bi amping. I don't turn them off. Either amp, even though fully burned in takes a lot of hours before it settles in completely.
