Will an Isolation Transformer Help My Digital?

Hi Lowrider,

I read through the prior thread that I think you are referring to, to refresh my memory. 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), and given that the noise was eliminated when you plugged the CDP into different and more distant outlets, my guess is that the isolation transformer stands a reasonably good chance of resolving the problem. Obviously, though, I can’t say that with certainty, in part because its specs provide no indication of what frequencies its "35-65 db noise suppression" apply to. So that spec is pretty much meaningless.

Also, what was the upshot when the Sunfire tech looked at your amp, with regard to the fact that its chassis was inexplicably not connected to its safety ground?

Best regards,
-- Al

@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?

Lowrider, I'll bet the wall-wart is a switching power supply. If so, it may be feeding noise back into your wall. Why not try an old laboratory power supply capable of the same voltage, instead of the wall-wart? "Old" being the operative word, before switchers became the order of the day.

Just a wild guess.