Buzz trnasmitted to speakers from amplifer

Generically, if your amplifier transmits a low level buzz to both your loudspeaker with no inputs connected (only XLR inputs available into amplifier)would this indicate some faulty engineering in the amplifier? Might there be a fix?...amplifier is plugged directly into wall outlet.

This buzz is only audible 3 feet from the loudspeakers and not heard with music playing.

Thanks for your input.

Brian