Home Theater Questions? Ask a Technician for Answers ASAP
Hi, I'm Nathan.Sorry to hear that you're having trouble, but I'll do my best to help you. Please give me a few moments to review your details here.
B channel has it's own amp (internal) but it is "assignable", so for a 7ch amp, you have the 5 main room speakers typically, the extra 2 can be assigned as B, or zone 2 (depending on model) or B channel. Those speakers sound like they might be powered type speakers meant for use with a guitar or other instrument perhaps. If you could shoot me a photo of the jacks on the back I'd have a better idea of how it could be used.
Z2 is different, on some amps (not your model) it would be used to drive the speakers, on yours it would really be for use with an external amp though, you'd use the B channel in this case, and volume is primarily managed via the volume control knobs in those other rooms.
Yes you can overload the amp running them like that, really the main intent of the B channel is to run either A or B, rather than both together (though it can be done).
You may be better off actually purchasing an external amp to drive your other speakers, it would take some load off the receiver.