2. tech-talk
  3. 150289-110508

AC Dedicated Line

Hello guys
I will run three (3) dedicated AC power lines: one for my stereo system (power amp, preamp, DAC, etc) and two for my stereo subwoofers (one line for each one).

These three circuits will be connected directly to the main AC board of the Electrical Comany wich provides me the service right at my door.

They will all share the same ground cable, wich I will connect to a dedicated ground bar, but I would like your opinion about sharing the "same neutral line" on these circuits. Could it affect the sound quality? 

If I have to send three different neutral cables, one for each circuit, I will need more cable to run through the house and it will be more expensive and complicated.

Please I would appreciate responses with real experiences. I don't want to start a technical discussion. I know at the end, in the main board, they all will share the same neutral line, so electrically it should be the same, but in this crazy audio world who knows for sure if soundwise it will be the same....

PS: by the way, I will run 4 or 6 mm2 cables (I guess about 11 to 9 AWG on the US scale). Here in Argentina we measure cables by square millimitres.
plga

Showing 5 responses by lowrider57

lowrider57's avatar
lowrider57
5,418 posts
 
You should consult or hire an electrician. If you run 3 lines of Romex 12/2, you will connect at the service panel to 3 separate circuit breakers (typically 20 amp).
Each line should have it’s own neutral and ground from wall receptacle to circuit panel. Plus this way the lines can all be wired to the same leg, or phase.

Cleeds states an important reason why you shouldn't share neutral and ground. Possible code violation and  sound quality may suffer.



lowrider57's avatar
lowrider57
5,418 posts
 
he reworked the single panel, keeping the larger draw appliances "away" from the music lines in, on the opposite side of the panel.
There are many threads related to this concept, consensus seems to be keeping high-current-draw appliances and SMPS devices away from audio circuits. I mean keeping a physical distance on the service panel for the audio line’s hot and neutral; ie, audio line breakers near top of panel. Refrigerator, air conditioner, etc. located lower.

My panel with subpanel is wired this way, although I disagree with all high current appliances wired to the opposite leg. The service panel must have a relatively even current draw on each leg.

I differ to @jea48 and @almarg on this subject.



lowrider57's avatar
lowrider57
5,418 posts
 
+1 Jea48 and Al. 
Heed their advice. Regarding your plan for the subs, expect to experience ground loop hum.
lowrider57's avatar
lowrider57
5,418 posts
 
I don't understand how you can connect to the AC line on the street. Is that how a residence receives power in your country?

lowrider57's avatar
lowrider57
5,418 posts
 
The hot, neutral and ground of the subs need to be hooked up the same way as all your components. They should tie into the same dedicated line.

Using a different AC line to the service panel while the subs are hooked up to your preamp will create a different ground potential (resistance). Very likely there will be hum. 
If you dont have enough AC receptacles, use a power strip for the subs, but keep them on the same 20A circuit breaker as the rest of your system.


More to discover