I've recently purchased a brand new mia jazz bass and an ampeg ba115. The problem is I'm getting radio interference when the guitar is plugged to the amp. I don't get any interference when the guitar is unplugged and the amp is on. I used to have a fender squire jazz bass with a fender rumble amp in the same room, same location, etc. but never had this problem. What should I make of this? Is there a problem with my equipment or is this expected? Also, the ampeg amp hums considerably more than the rumble. It shouldn't be a problem while playing but might be undesirable during recording. With the rumble I basically had zero hum. Is this also expected?