Will an Isolation Transformer Help My Digital?

@bombaywalla ,
Yes, there is a ground-loop due to the design of the Sunfire amp. I recently had the amp refreshed by Sunfire service and was in touch with Bob Carver who confirmed that the safety ground and the signal ground are tied together and do not meet at the chassis.

you've had your system for a while & this seems to be a very recent thing.
So, what has changed in your system that created this interference?

I started having this interference and hearing the high freq noise in January when I installed a new Atma-Sphere SE preamp (which is star-grounded). Amp into wall, Preamp & CDP into same Blue Circle and Furman.
Let me add that I only had the ARC CDP in the system up until then.
Almarg diagnosed a ground-loop before that due to the harshness of the CDP. I had a Rogue amp and did not experience any 60Hz hum.

I will provide the old link, but be warned, it is very long and goes on and on with tests I performed.

Also, the Tripp-Lite Isobar is brand new. It was an attempt to use isolated AC receptacles.
Getting back to the current ground-loop, I have removed the Blue Circle and used only the Furman pwr strip. AND, all components are currently using cheater-plugs.

The Chord Dac is new and is using a Switched-mode wall-wart as a power supply. Not the cleanest way to provide power.

The old link...(jea48 and Almarg provided much time and insight)
https://forum.audiogon.com/discussions/isolating-digital-noise-need-help?page=2

I'll leave with an explanation of Bob Carver's grounding design;
In the late 90s, the Sunfire 300 amp was mated with a stackable valve pre/pro. The amp used RCA and XLR (unbalanced) and fed it's AC into the pre/pro which was fully grounded to it's chassis. This was the ground potential for the rest of the audio system.

Hi Al.
See my explanation of the grounding theory. These early units were sold as a set.

And you’re correct that the noise was eliminated when CDP was plugged into different and more distant outlets.

Given that the noise was considerably less when you used the CDP’s stock power cord instead of the upgraded power cords you tried (the upgraded cords presumably having greater bandwidth than the stock cord, and therefore providing less attenuation of high frequency noise over a significant part of the spectrum)

Once again, correct. But, the noise was not eliminated. And now that I’m using a SMPS wall-wart for the DAC, the noise is considerably louder than a dedicated CDP. I intend to upgrade to a linear power supply.

@lak,
Always appreciate your participation. I found a thread where you speak to using an isolation transformer for the entire audio system, as you have done in your own house.
https://forum.audiogon.com/discussions/isolation-transformer-2?highlight=isolation%2Btransformer%2Bc...

Do you have any thoughts on using a iso transformer on the front-end of my system if indeed digital noise is being introduced?

terry, I'm sure your right since it is a switching power supply. I plan an upgrade, but that's not a bad idea as a test. Too bad I don't work with the bench tech guys anymore.

@bugredmachine.
It's a Chord QuteHD (same design as your DAC). And I got it for an amazing price, so I'm willing to pair a good Linear PSU with it.
Yes, the noise coming from the stock switching wall-wart is loud.

But my issue is two-fold; it's not only the Chord DAC, my ARC CDP sends interference/noise down into the mains.
Maybe it's noticeable because the CDP's output and my amp have very high gain.

I have been following the CPT thread and find it a most interesting and affordable way to provide balanced power to a system. But wouldn't all the components involved need to use the CPT PC's, in my case the amp, preamp, transport/DAC. Balanced power would prevent any ground-loop and interference.

@lak
Your audio rig looks wonderful and I have checked out your DIY electrical work and your transformer installations.
Am I correct as stated above that all my components would need to use the CPT PCs?

@whart
I have been looking at linear PSU's, such as Teddy Pardo, but a non-audiophile PSU with a large toroidal transformer is worth a look.
Same idea as terry9.

@ptss,
since there's no budget to change my power conditioning or convert to balanced power, have you ever used an isolation xfmr on upstream components?

@lak,
Thanks for setting me straight. So you are benefiting by using a CPT PC into a power strip. In my situation, if only the digital was in the CPT/power strip chain, IYO, would that isolate these devices? IOW, no noise bleeding back into the mains?
 My preamp would need to be on a separate line.

(And the Tripp-lite Isobar was a major disappointment. Not at all as advertised).

@ptss, thanks!
What size would you recommend for use with an ARC CD and a small DAC? I have seen xfmr's rated in watts; shouldn't they be rated in amps?

Also, is this Topaz good enough for high-end audio?
http://www.ebay.com/itm/191842008876?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Thanks to all. And thank you, Al for finding the acoustic noise spec. That unit would need to placed in a separate room.
And I knew that it was not a new item, but did not notice the wear and tear on the PC.

One thing I don't understand is why some iso xfmr's are rated in watts and some are rated in amps.
What size would I need for my 2 digital components...500 watts?
Again, I'll refer to the Tripp-Lite...
http://www.tripplite.com/isolation-transformer-based-power-conditioner-500w-line-noise-reduction-spi...

Many thanks, Al. Your knowledge and the time you spend contributing to the forum is much appreciated.
Jim