Isolating Digital Noise, need help.

@jea48, so far there is no high-pitched noise when using the stock PC on the ARC. Perhaps the Audience PC is not a good design for a digital device?

The stock PC sounds pretty good thru my power conditioner, but lacks the open soundstaging and depth of an audiophile PC.
I actually have a Synergistic Research Black PC on order for demo.

Since I'll be adding a DAC, I will still need to isolate digital from analogue components. Is a dedicated line the only way?
Also, I still need to work on the ground-loop problem between amp and preamp, and that will require a separate AC line.

Gotcha so this noise from the ARC is new or have you heard it combined with the Atma preamp the whole time?

jond, I've had to use the cheater on the preamp from the beginning due to 60Hz hum. Spoke to Ralph at Atma-Sphere and Almarg and the problem is due to ground loop thru unbalanced cables.
The Jensen Iso-Max didn't work on the preamp, there was still low-level hum and it changed the sonics of the preamp.

The ARC is the issue. No noise when using my backup NAD CDP.

lowrider57 you're sure the ARC is the issue? Have you tested other sources just to be sure? And you mention using a cheater plug on the preamp, did you try the cheater before of after you started hearing this noise?

@xti16, good question. I am hearing this noise since I added a new preamp (Atma-Sphere UV-1) which is much more transparent than the previous one and has higher gain.
 What's interesting is that it is so resolving, I can hear the change in noise from the power grid at different times of the day. I have a dedicated line, but live in the city. Late at night, the line is quiet.

It's an ARC CD3 mk II which is SS. And to answer xti16, I use a Jensen Iso-Max transformer to help with a ground-loop issue. It does cut the level of the high-pitched whine, but not completely.
I will be adding a DAC, so I need a plan for expanding my digital and to keep it isolated.

@jea48, yes I've used a cheater plug. You helped advise me on my dedicated line thread, where I wanted to add a line to remove a ground-loop between the amp and the preamp. Since I'm using unbalanced interconnects, the consensus was that an additional line would not guarantee the removal of the ground-loop.
I haven't installed that line yet since the layout of my circuit box is a mess and can't afford the electrical work at this time. So I'm using a cheater-plug on the preamp, as much as I don't like the idea, and a Jensen on the CDP.

My PC on the CDP is an Audience PowerChord, but I can try the stock cable for a test.

Lowrider is this a new problem that cropped up overnight? Is the whine present in both channels? Does your Arc have tubes? Tubes can make some very strange sounds especially when getting microphonic. If it does have tubes try tapping them lightly to hear if the noise changes.

I'm not a big fan of power strips. Have you considered a small isolation transformer or a small battery regenerator?

Another thought. Do you have a Nordost or Ansuz dealer close by. I ask because you may be amazed how well products like the Nordost QV2/Qk1 and or Ansuz Sparkz TC work. Maybe borrow one for an in home demo if you have an open outlet. I'm not sure if it would cure your whine because I've never run across a 'whine' problem due to power. I have an Ansuz MainzD8 power distribution and it does isolate analog from digital.