Amp makes clapping noise

Unfortunately no, the buyer is an elderly person and not able to try different options like cables and speakers. He is sending it back. I had used the original box and packing materials. I will have to try it out for myself when I get it back. 

Thanks oldhvymec. The sound comes from the speakers and not the amp itself. The pre-amp was not connected to it. Just the amp and the speakers.

I'm wondering the same as well if its an issue with the cables or the power outlet. Tried searching online but have not seen anything related to it. I'm confident about the amp and the shipping boxes themselves did not have any damage. 

As an update, I received the package back from the buyer, and as expected work perfectly fine. I was confident about it all along it may be something within the buyers other components that's causing his issue. I will have to refund the payment but the question is am I within my rights to ask for the fees I've paid to Audiogon and PayPal because there was no issues with the amp and preamp? Its less than $100. Didn't want to get a negative feedback for no fault of mine. 

Sorted out with buyer. Thanks y'all for your help.