Preamp Deal of the Century

I humbly suggest you take a close look at how all your cables are dressed. Where they cross, where they parallel each other, how they are seated in the rca inputs & outputs. That has always been the key to getting my system hum-free.

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.

My 20yo Chenin is quiet, all cords and IC;s have those foam pipe tubes cut to length and separates AC from the signal wires.

All components seperated on their own shelf, I had hum at one time and that seemed to resolve it.

@richmon A bit off topic but I wonder if your foam tubes might not unintended effects on the sound. Off hand, two theoretical hypotheses come to mind (although I’m not an expert): 1) the foam acts as an additional insulator that counteracts the developer’s intended design and construction of the cable(s); and 2) on another forum SR’s Ted Denny recently linked a video that speaks to how the fastest moving electrical fields pass mainly outside the cable, not through the wire, which raises the possibility that your tubes are interfering. For example, in the 19th century the first underwater (ocean) telegraph cables that were held together by iron sheaths were quickly deemed a failure because of the latter’s interference. Foam is not iron, obviously, but what evidence do you have that its properties or mere presence don’t interfere to some degree? The video Denny linked, "The Big Misconception About Electricity, is on YouTube:

My foam tubes are on the interconnects where the AC cord is nearby or crossing,  my goal was to eliminate or reduce those electrical fields in and around the AC from the signal. wire/interconnects. Sorry I wasn't clearer about that, no foam tubes are on the power cords.

I'm not smart enough to fully understand Ted's video but I presumed he was referring to AC flow and that didn't apply to the signal current flow.