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Isolating Digital Noise, need help.

I'm hearing noise from my ARC CDP thru my speakers presenting as a high frequency "whine" or "soft screeching." I need to isolate my digital from the AC line it shares with my analogue components. Running another dedicated line is not an option at this time.

I was wondering if a power strip with isolated receptacles, such as star-grounding, would be an alternative to a separate AC line.
As a test, I now have the CDP connected to a different outlet in my house and the noise thru my system is eliminated.

Would this type of power strip be an effective solution, and if so, I could use some recommendations. I have several layers of Blue Circle power conditioning, so I would need a strip with surge/EMF/RFI protection.
lowrider57
jea48
2,944 posts
 

I was wondering if a power strip with isolated receptacles, such as star-grounding, would be an alternative to a separate AC line.
As a test, I now have the CDP connected to a different outlet in my house and the noise thru my system is eliminated.

For a test did you try using a ground cheater plug on the ARC CDP? I would suggest you try that first.

It sounds to me from your post the power supply of the CDP is corrupting the power supply/s of the analog equipment. You might look into a power conditioner for the CDP to isolate the CDP power cord from the analog power cord/s.

Does the ARC CDP have a detachable power cord? If so are you using the stock power cord that came with the CDP or an aftermarket power cord?

If it is an aftermarket power cord you might want to make sure it is wired correctly. Make sure the Hot and Neutral conductors AC polarity are not flipped from the plug and the IEC connector.




 

 

xti16
1,495 posts
 
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.
lowrider57's avatar
lowrider57 OP
3,018 posts
 
@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.
jond's avatar
jond
3,400 posts
 
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?
lowrider57's avatar
lowrider57 OP
3,018 posts
 
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.
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