A/C interrupts music

[marce]

Try the ISO REGEN with another power supply, that will determine whether the PSU or the REGEN is the problem. If your speakers actually turn off I would suspect a brown out (a voltage sag when the ac unit switches on). This can be common in car systems when you turn the engine on (crank dip) and is a pain. The problem though does seam to be with the AC unit, it should not have that effect.