My lights dim when the AC cuts on, but the music is unaffected.
Obviously we want surge protection, beyond that I think its dependent on whether or not your voltage is consistent or not. Power conditioner vs Voltage regulator.
(I can see on my Furman conditioner that the voltage changes a bit, so I'm going to upgrade to an Accuphase 1220 balanced voltage regulator and be done with it. )
some day