My brother has a pair of 4311b speakers and he is presently powering them with a Carver 150 watt amp that has been acting up in one channel with static etc. At this point he is ready to give up on the Carver. I found two amps that I thought might work well with his 4311b speakers. First one is the Yamaha MX-1000u (260 watt/8ohm class a/ab). The second amp is a Threshold 400a Stasis amp (100 watt/8ohm class a). Are these two amps decent match and which of the two would you choose?