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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
58 responses Add your response
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.


lowrider57's avatar
lowrider57
5,400 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.


almarg's avatar
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almarg
9,670 posts
 
I agree with Lowrider. Even if the earth grounds are co-located, connecting the subs to the wiring and the breaker panel serving the rest of your home, while connecting the rest of the system to the new dedicated line and new panel, would risk ground loop-related hum and noise problems and in addition may very well compromise the benefits the dedicated line can potentially provide.

Given the effort and cost that is involved in installing this new line, and the associated breaker panel, why take those risks? Preferably have a second outlet installed, or if that is truly impractical for some reason use a high quality power strip, as Lowrider suggested.

Good luck. Regards,
-- Al

plga OP
184 posts
 
Thank you guys. 
ieales's avatar
ieales
1,201 posts
 
I didn’t 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.
Terminology: Ground ROD is in the earth and connects to the Panel Neutral BAR which connects to Transformer Neutral.

There’s more to ground rods than just sticking a piece of copper in the ground.

Adding two rods could reduce their efficacy in the event of a lightning strike, their primary purpose.

If materials differ, you could set up a galvanic cell which would eat one away. Ditto if perchance soil & moisture conditions differ dramatically at the two locations. Unlikely in a home installation but not outside the realm of possibility.

The 3rd pin is a secondary SAFETY path to return fault current to the transformer neutral to ensure enough current flows to trip the breaker. If you don’t return the 3rd pin to the transformer neutral YOUR SYSTEM IS LETHAL!
plga OP
184 posts
 
Hello guys
I've just installed the AC dedicated line.

Its just three 10 to 12 AWG wires (hot, neutral and ground) for my system, not the subs.

I havent included the subs (Boston Acoustics M Subs) because they dont have ground on their plugg (as many other subs, like SVS SB2000 for instance) so I figure out I shouldnt have ground loops or hum and I was right. On the other hand, latter on, if I decide to connect them to the line, I can do it. But today its somehow simpler this way.

The results are better sound on EVERY aspect: smoother highs, better detail, improved layering and 3D soundstage, stronger and better defined bass, etc.

I think its one of the best upgrades per dollar out there, period. 

Thank you all for your suggestions! 
almarg's avatar
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almarg
9,670 posts
 
Congratulations, @plga.  Enjoy!

Regards,
-- Al
 
plga OP
184 posts
 
Thank you Al. 




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