1. Wiring inputs and outputs that way will work just finely.
2. You may or may not hear a difference. If you don't have to buy more speakercable, TRY IT!
3. You will be driving your speakers with 400 Watts of rated-maximum power, and the sound should be more dynamic unless you listen at quite-low volumes. Actually, with 6-Ohm speakers, your amp channels could drive more maximum power, say, 150 Watts each, which is around the maximum-rated power of your speakers, so be careful--if you're a headbanger, you may be blowing drivers soon.
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2. You may or may not hear a difference. If you don't have to buy more speakercable, TRY IT!
3. You will be driving your speakers with 400 Watts of rated-maximum power, and the sound should be more dynamic unless you listen at quite-low volumes. Actually, with 6-Ohm speakers, your amp channels could drive more maximum power, say, 150 Watts each, which is around the maximum-rated power of your speakers, so be careful--if you're a headbanger, you may be blowing drivers soon.
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