WS-420 keeps blowing fuse
 

I ditched my stereo and installed the WS-420 in the same hole. I picked up a Harmon Kardon 12v Bluetooth adapter and plugged that into the RCA inputs. The Bluetooth has it's own fuse. After an hour or so of playing music the WS-420 pops the fuse. My speakers don't "hiss" and the amps are also separately fused.

Anybody ever have a similar problem?

Could the Bluetooth adapter be causing the problem? My options are to replace the WS-420 or pick up an RCA to 3.5mm adapter and plug my phone straight in.