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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
5,418 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
4,111 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.

lalitk's avatar
lalitk
5,614 posts
 
1 + lowrider57. 

I am using two dedicated line conditioners, one for digital sources and the other one for preamp/power amps to great effect. 


lak's avatar
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lak
4,688 posts
 
Whitecap, I believe  you are fine in your situation with one dedicated line. Adding a second dedicated line probably is not worth the extra expense at this point. In theory a second dedicated line or a third is the way to go however in the real world it might not make much difference. In my home I have four dedicated lines running out of my sub box to my main system and when experimenting with the digital components I'm not sure that I hear a difference. I do highly recommend an audiophile quality AC outlet, if you do not already use one.

terry9
2,354 posts
 
I take it you are still renovating. Is the breaker box in a utility room rather than in a living area? Because if it's in a utility room, you can use an isolation transformer between the box and your dedicated line, and use another circuit for the CDP if it's a problem.

Since isolation transformers can growl when they are doing their job, they really should not be in a living area.

I use three isolation transformers to keep noise to a minimum. It made high priced power cords obsolete - direct test in my system. Thus you kill two birds with one transformer - isolate your analogue system from the CDP, and also from the elevator and God knows what else. Not to mention, making high priced AC power cords obsolete.

Plitron makes very fine isolation transformers, suitable for medical equipment, and they sell directly to the public. Highly recommended.
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