Two things to say.

1. I use B&W CDM7NTs as my mains. I originally got them for a 2-channel audio system. I noticed a distinct difference when I replaced standard 2-wire copper cable with a pair of DH Labs Q-10 cables that were biwired. The DH Labs cable is relatively inexpensive, and you can buy cables used for about 1/2 the original price if you look on Audiogon or eBay. When I got my 1070 and a CDM Cnt I made up a third cable from DH Labs Q-10. I use 12-guage copper for the surrounds, and don't plan to change that unless I win the lottery.

2. I added an external phono stage to my audio system several years ago. First I tried a Creek model, but there was a lot of noise from FM radio signals, so I sent it back. I then found a Gram Amp 2 and it had less noise. At the suggestion of Graham Slee, the designer, I got a bunch of ferrite shields for the turntable's power cord and the interconnects running from the turntable to the phono stage and from the phono stage to the Amp. That fixed the problem and it was cheap.