Sub panel & isolation transformer voltage

Of course...but that's not what you asked. Going 240 all the way and then stepping down at the subpanel or going all the way amounts to the same thing. If it's a large house, and the stereo is far away from the main, you go off the subpanel. The only reason to do this is that the resistance is far less through the thick wires going to the sub. If the stereo is near the main, it's better to go straight. Either way, eventually you are connecting to your neighbors trash, so you need the I.T. HOWEVER....what problems does the I.T. cause,if any? Have you A/B'd with and without? What kind are you using?

I haven't installed an IT in my new house yet, but years ago I did have one and the difference of quality was quite noticable; deeper, cleaner bass, easier mids and less harsh highs. Much better image on the TV also, better voltage control it seems.

Homer, please post when you install your new IT, what model you end up getting, and the sonic results. Thanks!

Sure will, it'll be about a month or so since I'm doing the whole room from scratch, about halfway through now. I'll post some pictures if I figure out how to!