Will an Isolation Transformer Help My Digital?

I agree, it's more likely you have a bad device. This sounds like a digital power supply nearing the end of it's life.  Getting a noise isolation device is just going to mask the problem until smoke comes out the top. :) 

Best,


Erik 

I am experiencing noise from my digital components into my system. It presents as high frequency interference thru the speakers once the components are warmed up. This interference is being sent back to the mains and can be heard when music is being played or idle.

I’m using an ARC CD3 mk II CDP, Chord DAC, and a NAD CD player. I have a 20 amp dedicated line with Blue Circle power conditioning at the wall.
A Furman power strip for the low-current analogue components is plugged into the PC. Also feeding from the PC is a Tripp-Lite Isobar with isolated filter banks for the digital. The toroidal chokes in this Tripp-Lite power strip are not able to filter the digital noise.
My amp plugs into the wall duplex outlet.

lowrider57, 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?

How are you certain that it's from the digital equipment? All the components you cited are in wide use & mostly modern built meaning that hi freq clocks radiating out of the box is almost a very low possibility.

I'm thinking that you have a ground loop somewhere given that you use a power conditioner + a Furman power strip + a Tripp-Lite Isobar. One of these items is coupling to the RF noise & putting it onto your amps such that you can hear it thru your speakers. 

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.