The single largest jump in performance in the Class A series. Sonic presentation rich in sonic layers, textures and minute albeit never over etched detail.
30 / 20
The XA.5 amps are Class A (low rail voltage and high bias current) and the X.5 amps are high bias AB (high rail voltage and lower bias current).
The meters reflect current draw (bias).
About 25 deg centigrade above ambient. If your room is warm the amps will run hot, if your room is cool the amp will run cooler. On average they run around 50 deg centigrade - hot to the touch but not hot enough to burn or cause any harm.
Yes. Most improvement comes in the first 24-36 hours, after which the amps will continue to improve as long as they are left on.
Because it sounds better - pure and simple.
More power - less heat.