The Cabernet manual states:
"A gain adjustment knob is provided in case preamp is used with high gain power amps, if noise is an issue adjust gain until noise disappears." The same applies to the Chardonnay.
Adjusting cables is a separate matter. Power cables that cross should do so as close to 90 degrees as possible. I use those cheap rubber-covered foam isolator blocks one finds on eBay to keep cords from touching, and those and bamboo glass coasters held together with wood spindles (Michael's) to keep cables off the carpet.