Hey,
I've been playing around with the latest firmware for a bit...so far the capturing of the direct amp profiles didn't really work well for me, the full studio profile sounded much closer to the real deal.
but that's not really my problem, my problem is actually of a much more severe nature, since I fear it could potentially harm your cab (I haven't checked my Mesa 4x12 yet but really hope it survived)....
I'm using the speaker out on my powerrack to drive the 4x12 (like I always did) and "regular" playing sounds great (like it always did)....but when I played a low palm mute and let it ring for a second there was a HUGE volume buildup, totally overdriving and heavily distorting the speaker and everything else later in the chain (mic, preamp etc).
and I don't mean a slight "oh, that's overdriven, let's lower the volume" kinda distortion, but a full on "everything is farting and sounding like a square wave synth, I hope the speakers in the cab didn't die" - kinda distortion.
it doens't occur on chords or single note lines but only on very bass heavy material (palm mute on down tuned guitar).
Has anyone else experienced that problem yet?
EDIT: here's a sound clip so you know what I'm talking about (this is not a direct recording (which sounds fine), but the miked cab)