Surprised there has been no advice, though I'd imagine that balanced transformers for mains supply are few and far between in installations by this forum's members.
I have no experience of these; nor would I even contemplate the cost and complexity, but I have a good, reliable urban supply.
I do, however, have a fully discrete radial circuit installation (and earth rod), and would most definitely recommend one in your circumstances.
Firstly, I'd be sure about the location of your hifi, as not only is it difficult at best to move dedicated installations, but the siting should ideally be reasonably accessible to your incoming mains board/meter etc.
Happy to furnish details, but, depending on your pocket and ambitions, you'd need a separate consumer unit, beefy cable (pref. 6 or 10mm2 t & e), RCBOs for each circuit or, failing that, MCBs with a covering RCD. Sockets (if required) should be Crabtree (I've recently been informed) rather than MK.
This post'll bump it up, at least !