Welcome to the Jayco Owners Forum Buzter! Is it under the two yr warranty and did you buy it new? Our speaker buzzed also, and it was a matter of disconnecting some wire (sorry can't remember which) that the factory added incorrectly. If not under warranty, Jayco prides itself on supplying parts to any age Jayco.
The one complaint members seem to have is that the entertainment system sorta sucks in most of the recent models and have replaced them with completely different brands. While waiting for replies from some of those members on what they bought, try searching the forum under 'radio' or 'sound system' etc. Let us know what you wind up doing, as it may help others