Just got this head. It´s just like the Thunderfunk and the AMP420 with a few exeptions. It is really powerful with my two homemade 1x12" cabs and the sound is really warm, punchy and growly. The timbre and enhance controls can get me my sound and much more in seconds and the semi parametic Eq is really powerful. Mine is in great shape and I got it at half the price of a new Thunderfunk. Only problem is the last owner cut holes in the case at the top to make for better cooling. It is mounted in a rack case so it´s not a cosmetic problem. But how does this affect the cooling as I understand the aluminum casing was ment to work as a heatsink. Can I fit a blank aluminum plate on top of the old drilled top plate or should I just leave it?