I received a new GK MB200 from MF last night and need to decide whether to try to exchange it for another unit, return it or accept the way it is. (Edit - Video from post below) GK MB200 Hiss - YouTube I did a search in the 1000+ post MB200 thread, and obviously turned up a number of posts regarding hiss, but the subjects in the thread are broad and it started getting a bit dizzying. I got the impression that hissing was more common earlier on and had been eliminated or at least reduced in occurrence. I unpacked my MB200, connected it to a TCE RS212, centered the tone controls, and powered it up with the gain on 0. I immediately noticed a hiss. I was surprised because there was no volume and no bass plugged in. The hiss seems to remain present regardless of the state...cab/no cab, instrument cable/no cable, headphones or not, and all various switch positions. It is reduced by lowering the treble. So, the main question I have is are some people getting units that are completely quiet? Is this the norm? Are there people who are accepting some amount of hiss as an artifact of the relatively bright tone of the amp? I have to spend more time with it over the weekend, but my initial impression is that it's not acceptable.