Well I got this cab. When I plugged my Ashdown Superfly in I got this buzzing/ distortion noise. It sounds like something between a blown speaker and digital "overdrive". Trying to figure out if it is the cab or speaker I take it down to my dads studio where we plug it into a speaker power amp (the only source of sound I can get). Cab sounds fine. The music had a good amount of bottom end and we through some decent volume at it and the thing sounded totally fine. No buzz whatsoever. At this point I am thinking the Superfly is causing me the problem so I order a new head. Fender 250 HD. Got it yesterday, plugged it in and had got the same damn buzzing. The eq is flat. Even when I cut all the bass the head will allow me I still get a buzz. I get the buzz on low notes, high notes, harmonics, low volume or high volume. I can't imagine a loose screw is causing it as I hear it even when playing harmonics or any notes at the lowest of volumes. But why didn't I hear when I was playing music through it. The cab was thumping and it sounded totally clean with the music. Any thoughts?