If you mean an external higher quality PS, then, unless they totally screwed it up, yes.
Bad power is a stealth sound killer that is often overlooked. Music (but not Muzak(tm) has huge transient power demands and only a good PS can deliver. As Mikhail from Singlepower says, "An amp is essentially a modulated power supply." And modulated crap sounds like, well, crap. If the amp doesn't get the power it needs it will clip. Clipping is one of the most (to me) unpleasant distortions there is. In fact, one thing some EEs actually agree upon is that tubes clip more benignly. And according the this paper, clipping is more common in music playback than people realize.
In a previous house I owned, one of the largest (and cheapest) tweaks I did was to have a 10 gauge wire run from my breaker box to my living room to a hospital grade outlet. It was < $200 and it improved the sound tremendously. This was for a speaker system, but IMO, shows the benefit of good power.
But go by your ears and audition if you can or return if you don't feel it's worth it.
-=A=-