I have a UL902 and a UL212 Series 2 cab. It has this inherent 'warm' and 'thick' sound that I can't get rid of. Is this the power amp stage, or the cab. I have read on this forum that the class D amps impart a certain 'warmth' to the sound. I'm actually thinking of changing it for a Warwick Hellborg rig, but I was wondering if I needed to change all of it.