Before we start looking for culprits outside the system, maybe we ought to look for culprits inside the system. First, is the noise in both channels or only one? If only one, it's pretty easy to figure out the component that's causing the problem by switching cables from left to right.
Assuming it's in both channels, I'd suggest borrowing alternative components and swapping individual items out of the system. Once it's clear what component is causing the problem, he would do better to return it and look for something that actually works. For 10 grand, that's the least you should expect.
Assuming it's in both channels, I'd suggest borrowing alternative components and swapping individual items out of the system. Once it's clear what component is causing the problem, he would do better to return it and look for something that actually works. For 10 grand, that's the least you should expect.