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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
2,333 posts
 
My opinions again.

When selecting a device to filter your power, make sure that the output is better than the input from the wall. Not all consumer grade devices do that - or so I am told. Thing is, do they fix the problem you have? A computer uninterruptible power supply is great if you don't care about the wave form, but just need juice to keep a critical computer system up and running. Audio needs clean waveforms, and no DC. IMO. That's an isolation transformer.

Just put a 'scope on a voltage divider across the output. Get your retailer to arrange that. Any tech in the country can do it. The picture on the scope should look like the sine wave from a calculus text. Compare the picture from the device under test to the raw output from the wall. If the device isn't better, if it has jagged steps or other grunge, don't touch it, even if its free, unless your wall power is truly ugly.

If you can't test directly, a good rule of thumb is to use industrial grade equipment, or better. That stuff has to work - their customers are sophisticated enough to test it and demand it. I hear the difference, so I use it.

Just my opinion. YMMV

terry9
2,333 posts
 
Should add, that for a motor controller (as in a turntable), it is a good idea to synthesize the waveform with a special circuit. But that is a very special application, and low power, and relatively low cost.

whitecap OP
121 posts
 
Many thanks for the helpful comments.  As it turns out, there would be just too much tearing out and redoing brand new soffits and walls, etc.  So, I am going to stick with the single dedicated line.  I will explore the various suggestions offered here.  In particular, Terry, thanks for the input about an isolation transformer, will consider it with my electrician.  
terry9
2,333 posts
 
My pleasure, Whitecap. Good luck with it all.

emailists
923 posts
 
I'm in Manhattan as well, and would love to hear your JL subs when your system is done.   I'm trying to decide as well what dedicated lines to install (I'm running off a single 20 amp right now). 
This thread has me thinking.   Since the digital (a dac only in my case) needs so little amperage, why not use the standard wall outlet with a small isolation device or power conditioner for that, essentially giving you two circuits.   I'm going to try that as well.   
Also I use an older ps audio quartet on my elaborate computer editing system (which also runs jriver for my stereo) just to try and keep it from polluting the condo's AC.   
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