Hi, I have a pair of this wonderfull Amps. My english is not so good - sorry ! These Amps are a bit powerfully than the Poa-6600 / A. More deeper Bass and more crisp highs. Is easyer to hear longer sessions, the amps never nerve. It´s sounds a little like Tube-amps whit the power of the big DENON - monoamps. They runs very hot, but is imposseble to break it. It´s normal in class A secriut. They were sell 1983. limited of 250 Pair cost 5500 $.