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Dedicated Line(s), One Line or Two?

We are renovating our NYC condo (in a 1960, 175 apartment building) and using it as an opportunity to run a dedicated line direct from the breaker box to the two-channel system (20 amp, 12 gauge wire).  The contractor ran the line (singular) as requested.  But now I'm reading that ideally we should have two dedicated lines, one for the digital source (CDP) and one for the analog components.  The problem is that running the one line took a lot of work, chopping wall channels, removing molding, etc., and the new line has already been closed in.  I could have it redone to add a second line, but it won't be easy or cheap.  (Obviously I should have done more homework sooner.)   Questions: How much "dedicated line" benefit am I giving up if I just stick with one line, and have two duplex outlets on that one line?   Put differently, having gone to the trouble to add one dedicated line, will I still get enough improvement, so as not to feel like a complete fool for not adding a second line?   Is there a material downside to having digital and analog both drawing power from the same line?  Any input appreciated.  
whitecap
lowrider57's avatar
lowrider57
5,393 posts
 
It’s’ when you add computer audio into your system that a second line is absolutely necessary. Computers generate noise through the power line.
I wouldn’t worry about a second line, with your system a 20 amp breaker is just right. If you had mono blocks, you might need a separate line due to high current draw.
Start listening to music and see how it sounds.
tls49's avatar
tls49
1,351 posts
 

As they say, hindsight is 20/20. Yes, 2 dedicated lines, 1 analog and 1 digital will achieve much better isolation between the analog and digital components. Some power conditioners can also provide isolation as well, but IMHO, it can't be as good as separate dedicated lines.


saki70
907 posts
 

What tls49 said .

But , as Whart said , it is not a cure all for noise . I have two separate

lines , on different breakers with isolated ground , but still get a little noise from my CD player . Very slight and can only be heard without music playing .

For the power aspect , it is a no-brainer ...2 lines ! I look at it as 'future proofing' .

Good Luck .

lowrider57's avatar
lowrider57
5,393 posts
 
saki is right about possible noise from your CDP.  But rather than encour a great expense adding a 2nd line, see how your system sounds and check for noise on the power line. A dedicated AC line does not guarantee noise free power, since you're dealing with the outside power grid.

Power conditioning can lower the noise floor, so can high quality power cables. If the ARC CDP does add noise, there are ways to isolate it from the analogue components. 
2 lines would be best, but you have to weigh the added cost vs. how your system sounds now.
mitch2
3,687 posts
 
I agree with lowrider57, listen first and then, if it sounds good, simply enjoy.
Had you asked before doing the work, I would have suggested installing 3 lines at 20A each or, if total available amperage was a problem, then 2 lines at 15A (for amps) and one at 10A (for front end gear).  Having one of the outlets spaced a short distance from the other two, but still along the equipment wall, would have provided a nice option in the event you ever decide to switch to monoblocks.   I also would have suggested the three breakers for the audio lines be located on the same side of the electric panel.  Finally, I would have recommended using 10awg romex wire,  regardless of what your electrician says is "minimum" code for the breaker size.

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