Hi Nathan,
Any number of things could be causing the dropout. The most obvious one would be a small short in the speaker connections for that channel, but I'm assuming you have checked them carefully at both ends. There are two protection mechanisms in our amplifiers, one is over-current and is provided internally in the Class-D audio controller IC and the second, external mechanism handles high/low input voltages, DC offset, and thermal. In some conditions the external protection can latch and requires powering the amplifier off and on again to reset. I'm not sure how long you've had your ADA1250, but if it has been for a number of years I would suggest purchasing a can of compressed air (available at most electronics or computer stores), removing the top of your amplifier after it has been unplugged for at least 30 minutes, and spraying the tops of the amplifier modules closest to the rear panel to clear off any dust or debris. Believe it or not, we have had a few circumstances where a thick layer of dust or dead bug has caused an intermittent short, and at high switching frequencies it does not take much.
Thanks,
Andrew
