LVC said:OK attached is a copy of the patch and a link to a recording I made with my iphone (buzz is more pronounced in person).
I get the same "fret' type buzz with ALL of my guitars.
It is annoying as hell -- especially if you are a typically clean player.
Link to sound example
http://soundclick.com/share?songid=8976188
I dunno man.
Based on the rest of this thread and your comments about this only happening after the Axe has heated up, and the fact that your new unit appears to be fine, and on Cliff commenting about the possible bad solder joint; it appears like you really had a hardware malfunction.
But based on your clip and on the posted sysex files it sounds to me like you've just got a bit of dirt on that preset that would go away by lowering the Gain or the Master parameters.
I.e. I don't hear "fret buzz" per se. What I hear is the amp being overdriven when you hit the strings hard enough.
You also might want to turn down the Input knob a bit.