I would be hesitant to add more power to the system until I knew what happened the first time or I had some length of time to satisfy myself it was something that won't occur again. I would run the 2150 hard with those garbage speakers (4 ohm) to make sure it is not the problem.. One thing you could do is ask Outlaw to check it out for you to make sure it is good to go. While I don't think the 2150 is at fault it never hurts to be cautious.

If music is your prime use of the 2150 why not connect your PC directly to the 2150s USB port?
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Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner