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New dedicated lines have high noise floor.

I just installed two dedicated lines for my system.  Each is on its own 20a circuit breaker.  I used 10 gauge hospital grade MC cable (exact same length) and Cardas 4181 duplex outlets.  I was expecting a quieter noise floor and better sound.  I have a 3x to 4x increase in the noise floor compared with a regular outlet nearby.  One of the circuits has a "crackling" sound.  For the best results, I need to put my amp and source equipment on a single outlet.  If I use both the sound gets worse.  Any ideas?  I need to have my electricians come back, but would like to have some audiophile wisdom for support.
pg62

Showing 2 responses by erik_squires

erik_squires
16,644 posts
 
Before you call your electriticians, there is something for you to try.

Turn off every other breaker in the home. If the noise persists, it's on the line, or from the outside. If it all goes away, it's coming from elsewhere in the home.

If your breaker box is old, you may also want to ask about arc detecting breakers.

Best,
E
erik_squires
16,644 posts
 
The crackling is a real issue.  Please have it checked, you may have arcing somewhere.

The other issue, is one I have warned about before. Having too good of a connection to the panel means you may get closer to any noise from outside.

A better solution may be to run 240 to your room, and then use a step down balanced transformer, like from Equitech, to feed your gear. This is fairly cheap to do, as you've already run the wiring. Just need a new, dual pole breaker and appropriate outlet.
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