Hi, good morning,honored to be part of Talk Bass community. My name is Angel, my friends call me Rabbit, i recently bought the amp in question and i have noticed there is a hiss noise coming from it even when no instrument is connected. When using pedals sometimes it worsens, my compressor helps but, the issue baffles me sometimes, i will try another power outlet and try the ground connections between them (link them together) and will update the results, my instruments are passive Fender and Squier. Im feeding the amp on the -15 db input jack. Thanks in advance for any input and/or your time friend.