I don't think I'd worry about it too much. I'd be surprised if the extra 4 channels use all that much electricity when idling, and heat has never been an issue with the 1050 as long as it is well-ventilated (i.e. has enough room above it).
I might even go as far as to say you really wouldn't like to turn off those channels, because if wear and tear IS an issue, then you wouldn't want four of them sounding different (newer) than the other two in a few years.
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Matthew J. Hill
matt@idsi.net
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Matthew J. Hill
matt@idsi.net