I am getting a low level hum from my Burson Soloist SL MKII amp. When I turn on the amp,with volume all the way down, I hear a low level hum only on the left channel. Even with my interconnects disconnected the hum is still there. I tried another amp, but no hum. I'm assuming this may be transformer hum, but not sure. Assuming not a ground loop either since my other amp is ok, but again,not really sure. Everything sounds great when listening to music, but hear the hum when the amp is quiet. Thanks for any help or advice.