Following your comment, Vanman, I have connected my remote to a lead-acid car battery. I really didn't think it'd make any difference, but the soundstage is much wider and the noise floor [1] is much improved.
In fact, I was playing some tunes and the missus came in and said "B&gger me, that sounds good - what have you done? It sounds great!".
[1] What is noise floor anyway? I mean who hears 'noise'/hiss/interferance through the speakers on quiet bits? So what do people mean when they say the noise floor has improved? Really - someone help me here.