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
cleeds
6,273 posts
 
plga
I will connect the line to the main breaker of the Electrical Company who supplies me the service. Not the street!!!  I meant I will by pass my house's main breaker.
I do not think that complies with NEC - you'll also have to check your local code. That is definitely not allowed where I live.

I will connect a dedicated positive, a neutral and ground. The latest will be connected to a new copper bar, wich I will bury on the ground.
I'm not sure what you mean by "dedicated ground." All grounds and neutrals must be connected together inside the service panel. No exception - that's NEC. Also, some local codes require more than a single ground rod so again, so check local code.
almarg's avatar
almarg
9,670 posts
 
I will only connect my system to the line, not the subwoofers.

I’ll add to what Jea48 has said above that IMO it would be far better to connect the subs to the new dedicated line, as well as the rest of the system.

Based on what has been said earlier, including your own measurements that you described, it seems clear that 20 amps at 220 volts should be sufficient to power everything.

And by having the safety grounds of different components in the system connected to different earth grounds the likelihood of hum problems, high frequency ground loop-related noise problems, and even serious damage to the system if lightning induced currents in the earth cause a potential difference (i.e., a voltage difference) between the two ground points, are all considerably increased.

In any event, good luck as you proceed. Regards,
-- Al


jea48
4,788 posts
 
@cleeds,

He lives in San Juan, San Juan, Argentina



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.
plga OP
184 posts
 
Thank you guys!

I didnt consider ground loops, so I will interconnect both ground bars on the entrance or I will keep one single ground bar for all circuits, new and old.

On the other hand, I will ask my electrician, but I guess there’s nothing legally wrong here about connecting the breakers of the new line to the output of the main breaker of the Electric Company. Is there any electrical risk?

Finally. I have the subs connected to my preamp RCA outputs as the power amp uses XLR. I would prefer to just have one IEC plug, at the end of the new line, to connect to my DC Blocker input and skip installing an extra outlet to feed the system plus the subs. Do you think I will have hum issues or ground loops if I just connect the system to the new dedicated line, but the subs to my home circuits? I mean connecting everything to the same ground bar at the end.

PS: the total length of the new line is about 40 to 45 feet.


More to discover