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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
terry9
2,353 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.
whart's avatar
whart
3,056 posts
 
Pretty clever there, Terry. Rather than using the transformer to isolate the digital side, use it to isolate the analog side from everything else via the dedicated line and plug the CD into a non-dedicated line.
It’s another visit from an electrician, but not a wall buster, and you’re recommending just a naked transformer, right, not a whole box with the bells and whistles (additional outlets, Faraday cage, breaker, etc).


terry9
2,353 posts
 
Thank you, Whart.

I use naked transformers in an garden variety electric utility box. But it really depends on the local electric code, and the expertise of the inspectors, because some inspectors get bent out of shape unless its a finished, boxed unit. Plitron sells both kinds, certified UL etc.

If I were doing it again, I'd talk to the electrical inspector before doing anything. And I'd try to make him work for me, not against me. Experience teaches.

rbstehno
1,473 posts
 
I just built a custom house with a dedicated audio room and put in 3 dedicated 20 amp lines terminated right were I'm placing my gear. It is much cheaper to put more lines in when being built than to have to add them later. 

wrm57
1,054 posts
 
Indeed. I had my downstairs remodeled two years ago and put in four 20-amp lines coming off an 80-amp subpanel. I use them all: one each for amp, pre-amp, and phono stage; then the leftover one for digital, etc. I even sold my RSA Dimitri. Everything just sounds better plugged directly into the dedicated lines (with Furutech GTX duplexes and cover plates). So, I’d advocate for as many as possible.
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