I just got my new GK Backline 600 amp and GK Neo112 cabinet yesterday - they sound fantastic. But when everything is turned on and I'm not playing there seems to be a very low level "hiss" coming out of the speaker. It sounds like "amplified air" if that makes any sense. This is my first real rig so I don't know if this is typical - I never noticed this sort of thing with my BL112 combo unless I turned the volume way up. Overall it's not a big deal and I can minimize this noise by adjusting the Level, Master, and Boost knobs. I was just wondering if this is normal. On a side note, when I unpacked my BL600 I noticed a wire was pinched under the sheet metal enclosure, so I took the cover off and moved the wire out of the way. The wire was flattened out but the insulation was not broken so I'm sure it'll be ok. It isn't a big deal but it was a little dissappointing to see such an obvious manufacturing defect on a GK product, and it does make me wonder about the quality control in their China factory. I will give GK credit on their customer service however; I emailed them about the problem and received a response within about 20 minutes.