I think when people say musical it is often in the direction that @ghdprentice refers to, although it doesn't have to be with tubes. It often describes attributes that can be opposite what you want in a home theater setup (speech may become less clear during busy passages, for example). So something like what @adsell does gives you the both of best worlds.
With respect to your other question about the difference from a different amplifier, definitely depending on what you switched to the sound will change as well. If you pick a new amplifier that is designed similar to your existing Adcom, the difference will be minimal or inaudible.