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Dedicated Line Noise Filter?

I don’t know if what I’m seeking exists, so I’m asking the experts.
I have 2 dedicated lines installed; one for analogue, one for digital. They originate at a sub-panel off the main circuit box. The sub-panel is connected by the hot lead and has it’s own ground including a second grounding rod. There is a home surge protector installed at the main circuit box.

I have passive conditioning on both lines for the components, yet I’m still hearing noise thru the speakers (from about two feet away). I live in a city and I suppose it could be dirty power from the grid.
Now to my question; is there a noise filter that can be installed at the site of the circuit panels? My electrician offered a surge protector with noise filtering (plus EMI/RFI), but was very expensive. So, is there a device that can be installed upstream to lower the noise floor?
Many thanks.
128x128lowrider57
lak's avatar
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lak
4,619 posts
 
 A friend suggested the 5 KVA because he knew it was large enough for most audiophiles systems and would not bottom out. Other than that I'm not sure how to figure the needs but I'm sure other more knowledgeable people on Audiogon could assist.
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cleeds
5,943 posts
 
lak
A friend suggested the 5 KVA because he knew it was large enough for most audiophiles systems
5KVA works out to 5000 watts - assuming you have a good power factor. That might be sufficient for a small system, but obviously undersized on even a 15A line.
jea48
4,416 posts
 
5000Va / 120V = 42 amps.
gdnrbob
4,444 posts
 
For $750 you would be done with the problem, rather than adding another component/layer. Even better if you can buy yourself for less.
Your electrician seems to be a good guy, if he lets you provide materials.
Though, if you let him install the brand he offers, then he will probably stand behind it should anything go wrong in the future. I'd ask him why he thinks his brand is better than the less expensive ones.
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almarg
9,670 posts
 
The sub-panel is connected by the hot lead and has it’s own ground including a second grounding rod.
Lowrider, my understanding is that a sub-panel should have hot, neutral, and safety ground all wired back to the main service panel, and safety ground (which may or may not be connected from the sub-panel to earth) should only be connected to neutral at the main panel, and NOT at the sub-panel. (Jim/Jea48, correct me if I’m wrong about any of that). Is that how your sub-panel has been wired?

More relevant to your issue, though, have you tried powering the entire system from just one of the dedicated lines coming from the sub-panel? I realize that installing the sub-panel and using its two dedicated lines lowered the noise floor substantially. But using separate dedicated lines for digital and analog components, while certainly beneficial in many cases, in some cases can cause or contribute to ground-loop related noise. And perhaps the improvement the sub-panel installation provided occurred mainly as a result of the new wiring, rather than having separate dedicated lines for digital and analog. Especially if the type of wiring was changed when the sub-panel was installed, as there are several ways in which wiring type can affect noise issues.

Best regards,
-- Al
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