My brand new 552 had a relay get stuck and I lost my left channel completely, although I was surprised by that assuming that the quality assurance for a product of this cost would be super tight, nevertheless I figured many things can happen during shipment stages (I live in Dubai so it is not as straight forward for Naim to control the entire supply chain)
The worst for me was the wait, it took weeks to get a brand new unit shipped back… But when I listen to it now, all is forgotten and I grin ear to ear with joy as this pup sounds like a champ… no regrets.