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Braiding the AC mains feeding a power amp.

104.166.247.19
Posted on December 4, 2016 at 21:07:21
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
 What affect would braiding the branch circuit wiring installed in metal conduit have on the sound of a power amp?

The conduit is about 8ft long.

The duplex receptacle used is a Hubbell hospital grade, IG (Isolated Ground) type.

The wire gauge is #12. Just a guess the wire is stranded.

The hot, neutral, and green insulated IG equipment ground are braided together. (The IG ground wire is connected to the ground bar in the electrical panel)

The power amp is a Boulder 3060.


Any thoughts?

 

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RE: Braiding the AC mains feeding a power amp., posted on December 5, 2016 at 16:50:44
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 Hi jea48,

Do you mean extending the in-wall AC wiring through a metal conduit into the AC input of your power amplifier?

Cheers, Duster

 

RE: Braiding the AC mains feeding a power amp., posted on December 5, 2016 at 21:48:13
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
 Hi Duster,

Thank you for responding to my posted message.

A guy on another audio forum built a new audio room and hired some "expert" to design the electrical system for the room. He is not happy with the sound from his system now.

He has a sub panel now.

He has several dedicated branch circuits installed.

All the circuits are installed in their own metal conduit. I am pretty sure, steel conduit. (Would not have been my choice. But maybe because of the electrical code in his area it may be required. Don't know.)

The guy says the branch circuit wiring installed in each conduit is braided together. The hot conductor, the neutral conductor, and the green insulated equipment grounding conductor.

My question is could this braided wire installed in a steel conduit be causing his problem. Especially for the power amp. To me even though the wiring is a branch circuit fed from the electrical panel it looks to me to be basically a shield braided cable. The 3 conductors are #12. I also think they are stranded wire. He didn't say if it is a factory braided assembly.

.

Here is his first post:

I had a custom room built and spared no expense. Hired a power consultant who designed a system with a 15KVa isolation transformer and a custom breaker panel that feeds only the audio room. System incorporates isolated grounds and IG outlets. The advantage I have is that I know how my system should sound because I only changed one piece of equipment from my old to new room. System is Wilson Alexandria, Boulder 2110 pre, 3060 amp (had 2060 before and they sound very similar) and full vivaldi stack. System had incredible detail and thunderous bass. Now has decent detail and soggy bass (hyperbole). After a year, I had the electrician take the isolation transformer out of the system and run a new line from the street to the breaker panel. Everything is much better now, but still has a layer of syrup over the presentation that shouldn't be there and loose bass. Room acoustics are a bit different, but the power is the biggest difference. What gives?


His second post. His response to mine:

In metal conduits. Single run of 12G braided wire in each conduit. Run from subpanel is <8 ft in all cases. Probably 20 or so lines coming of the subpanel. Don't know about the interconnects. There are 2 legs, but all my equipment fits on one leg. Old room had lines slowly added over time. Amp was running 240 in there as well. I believe it was wired with 10G solid core cable. There was a mix of metal and "plastic" conduits and boxes in the old room. ( BTW, had serious ground loops in the old room, but the Boulder gear was fairly impervious to it. I demoed a single ended Lamm amp and it buzzed like a fiend!) Using a mix of hubbell and voodoo (cryoed hubbell outlets) in new room. Plastic plates.


So what do you think? Any ideas?

Jim

 

RE: Braiding the AC mains feeding a power amp., posted on December 5, 2016 at 22:10:43
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 Tri-braided cables are good in theory, but not so much in practice, IMO. What cable maker produces tri-braid in-wall AC wiring, or is it a totally custom build product from end-to-end, threaded through a conduit?

 

RE: Braiding the AC mains feeding a power amp., posted on December 6, 2016 at 07:10:55
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
 Tri-braided cables are good in theory, but not so much in practice, IMO.

In your opinion do you think the braided wires inside a steel conduit could be causing his problem?
Here is what I see with the construction of the branch circuit wiring.
It has 1 hot conductor that is 120V above ground and it is braided together with 2 grounded conductors. (The current carrying neutral conductor, and the safety equipment grounding conductor). And then the braided cable is installed in a 100% shield, a steel conduit.

**EDIT: The power amp is fed by 240V. Not sure if that would make any difference with the 2 hots and 1 equipment ground wires braided together.

For a 120V shielded power cord have you ever braided the hot, neutral, and equipment ground wires together? I have heard of twisting the hot and neutral together and then running the equipment ground straight along side the twisted pair. Or just running the 3 wires tightly together in a continuous spiral twist the entire length of the cable.

If you do not think his problem is the 120V branch circuit wiring, what else do you think it could be?

When I asked him how long were the branch circuit runs he answered all were less than 8ft. (<8ft) If that is the case his sub panel has to be really close to all the wall receptacle outlets. Not much distance (wire length) for decoupling of the audio equipment power supplies from one another by using dedicated 120V branch circuits. Could that be a problem?


What cable maker produces tri-braid in-wall AC wiring, or is it a totally custom build product from end-to-end, threaded through a conduit?

I asked him if the braided wire was a factory made assembly or was it made on the job? He did not respond to the question. Do you know of anyone that builds and sells a braided 12 gauge power cord in bulk?


 

RE: Braiding the AC mains feeding a power amp., posted on December 6, 2016 at 08:15:05
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001
 I have never heard of tribraded romex. Maybe it added too much capacitance. Sounds like it was a costly mistake!

Dave

 

Dave the in wall branch circuit wiring is not Romex., posted on December 6, 2016 at 08:37:02
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
 The three individual #12 insulated conductors are braided together and then pulled into an empty conduit. (The conduct runs from the electrical panel to the wall receptacle rough-in box.)


Maybe it added too much capacitance. Sounds like it was a costly mistake!

I don't think it is a capacitance or inductance problem. I think the braiding pretty much eliminates them from the equation. Though I could be wrong. What does the braiding of the 3 wires do to magnetic fields surrounding the hot and neutral current carrying conductors?

My thought is, what impact might the braiding of the hot, neutral, and equipment ground wires together have on the electromagnetic wave that is traveling from the source, the electrical panel, to the load, the audio equipment. Especially the power amp.

 

Braiding BY HAND would be crap. With all the variables in the spacing..., posted on December 6, 2016 at 15:15:00
Smelly_Socks
 Machine braiding is way better than hand braiding. N matter how careful hand braiding would be, it is going to be sloppy.

IMO the best way to "DO" in conduit would be hot/neutral machine twisted pair. With the ground alongside.
If you wanted to get 'fancy, three or four ground wrapped to surround the twisted hot/neutral and keep them from touching the metal walls of the conduit. Or even some way (Spacers?) to hold the twisted pair centered.
The ground would not matter in the spacing, just lay it in there someplace..

I tried braiding a powercord ONCE. It was junk.

 

RE: Dave the in wall branch circuit wiring is not Romex., posted on December 6, 2016 at 21:09:51
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001
 Everything from the outlets to the breaker in my system is Romex. What is it that you have? Is it code?

Braiding dose add capacitance. it is usually not enough to hurt anything, but it is a possibility. I have never heard of a braided branch circuit, but I don't know everything in the universe.

Dave

 

RE: Dave the in wall branch circuit wiring is not Romex., posted on December 6, 2016 at 21:32:24
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
Everything from the outlets to the breaker in my system is Romex. What is it that you have?

Mine too. 10-2 with ground. Outlet rough-in boxes are plastic.

Dave,
Please read my original posted message. EDIT: Sorry Dave, read my response to Duster. Link is provided below.

All of the guy's equipment is fed from branch circuits with braided #12 wire installed in conduit.

I was wrong on the power amp. I just leaned the amp is not fed with 120V but rather 240V. Not that, that, is causing the SQ problems.

 

RE: Braiding the AC mains feeding a power amp., posted on December 7, 2016 at 09:50:28
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 If the steel conduit is magnetic/ferrous, I would consider another option, if possible. In fact, if the in-wall AC wiring is only 8 feet from the sub panel, I would suggest the wiring be replaced with cryo'd 10 AWG Romex, since it might be possible that braided in-wall AC wiring run through a steel conduit is coloring the sound in some manner. I've always considered a tri-braided cable to be an easy way to build a DIY power cord from scratch rather than a superior geometry. my 2 cents

 

RE: Braiding the AC mains feeding a power amp., posted on December 7, 2016 at 12:15:00
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
If the steel conduit is magnetic/ferrous, I would consider another option, if possible. In fact, if the in-wall AC wiring is only 8 feet from the sub panel, I would suggest the wiring be replaced with cryo'd 10 AWG Romex, since it might be possible that braided in-wall AC wiring run through a steel conduit is coloring the sound in some manner. I've always considered a tri-braided cable to be an easy way to build a DIY power cord from scratch rather than a superior geometry. my 2 cents

Duster,

Thanks for your response.

It may be a local electrical code issue that dictated conduit had to be used.

IF I had been the one advising the guy I would have recommended he use 2 wire with ground MC aluminum armor cable. That is if it met the local electrical code conduit requirement.

As for what the guy has now I too think his problem is the braided cable installed in the steel conduit. I told him in the thread I thought that was more than likely his problem.

I sent off an email to the guy this morning asking if he had any luck solving his problem. Will see if he responds back.


If he does respond back and the answer is no I am going to recommend he hire an electrical for a day and just run a few new exposed Romex cables just on the floor over to his equipment. The electrician could just install some plastic outlet boxes on the ends of the Romex cables. For the duplex receptacles outlets just pull what he needs from the existing wall outlets.

Yeah, it might cost him around $800 but that's peanuts compared to what he has invested in his audio equipment. Not to mention he has been fighting the SQ problem from his system for a year.
Jim

 

RE: Braiding the AC mains feeding a power amp., posted on December 7, 2016 at 12:52:48
Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002
 It seems to me there is a possible issue of the magnetic fields being affected by a tri-braided cable run within a ferrous steel conduit, or the wire itself might be sub par, such as using THHN wire for the application which is terrible sounding, IME. This is not from an EE expert based POV, since my audiophile experience is limited to what I've gathered from a subjective POV over the years.

Perhaps the most important information that needs to be found-out is why the installer chose to use an unconventional wiring method. If the reason is based on a far-reaching desire to provide what sounds best to his ear from an anecdotal POV, I see no reason not to recommend that a more conventional in-wall AC wiring method be implemented for audiophile purposes as a rational attempt at a solution. It's a no-brainer option IMO, since there is no risk of ultimate failure based on the prevailing wisdom of using Romex or another audiophile-approved in-wall AC cable vs. a tri-braided "mystery cable".

The bottom line is, if there is no other reason discovered for unsatisfactory audio performance other than the AC delivery at the wall, try to fix it with what's known to work properly, IMO.

 

RE: Dave the in wall branch circuit wiring is not Romex., posted on December 7, 2016 at 14:39:34
Crazy Dave
Audiophile

Posts: 14371
Location: East Coast
Joined: October 4, 2001
 What confused me is that you said it was stranded. I don't think there is such an thing as stranded Romex. I have also never seen a 240V amp, but have read they do exist. That is out of my sphere of knowledge though.

Dave

 

RE: this is the issue, posted on December 8, 2016 at 10:03:53
Cpk
Audiophile

Posts: 1518
Location: PA
Joined: May 13, 2005
 His system will sound better doing away with the conduit. Any metal conduit will effect the sound

 

Agree. But how about aluminum? Maybe MC aluminum armor cable?, posted on December 8, 2016 at 10:52:21
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
 The guy has a separate room on the back side of his audio equipment that cannot be seen from his listening room. (I would guess the room is about 3.5ft to maybe 4.5ft deep running the entire width of the main listening room.) The electrical panel board as well as the branch circuit conduits are surface mounted. He might be able to use PVC conduit and PVC/plastic outlet boxes, if local electrical code allows it to be exposed. I think MC cable would be a better way to go. he could use malleable aluminum boxes for the receptacle outlets. What do you think? Any other Ideas?
Jim

 

RE: Agree. But how about aluminum? Maybe MC aluminum armor cable?, posted on December 8, 2016 at 11:11:30
Cpk
Audiophile

Posts: 1518
Location: PA
Joined: May 13, 2005
 My preference would be 10awg and plastic.

 

Your thoughts...., posted on December 8, 2016 at 11:26:44
jea48
Audiophile

Posts: 6770
Joined: January 5, 2005
 Here is what the guy has now.

All the dedicated branch circuits are installed in their own EMT steel conduit.

The guy says the branch circuit wiring installed in each conduit is braided together. The hot conductor, the neutral conductor, and the green insulated equipment grounding conductor. One dedicated circuit is 240V 30 amp for a Boulder 3060 power amp.

My question is could this braided wire installed in a steel conduit be causing his SQ problem. Especially for the power amp. To me even though the wiring is a branch circuit fed from the electrical panel it looks to me to be basically a shield braided cable. The 3 conductors are #12. I also think they are stranded wire. He didn't say if it is a factory braided assembly. I think it is....

.

Here is his first post:

I had a custom room built and spared no expense. Hired a power consultant who designed a system with a 15KVa isolation transformer and a custom breaker panel that feeds only the audio room. System incorporates isolated grounds and IG outlets. The advantage I have is that I know how my system should sound because I only changed one piece of equipment from my old to new room. System is Wilson Alexandria, Boulder 2110 pre, 3060 amp (had 2060 before and they sound very similar) and full vivaldi stack. System had incredible detail and thunderous bass. Now has decent detail and soggy bass (hyperbole). After a year, I had the electrician take the isolation transformer out of the system and run a new line from the street to the breaker panel. Everything is much better now, but still has a layer of syrup over the presentation that shouldn't be there and loose bass. Room acoustics are a bit different, but the power is the biggest difference. What gives?

His second post. His response to mine:

In metal conduits. Single run of 12G braided wire in each conduit. Run from subpanel is <8 ft in all cases. Probably 20 or so lines coming of the subpanel. Don't know about the interconnects. There are 2 legs, but all my equipment fits on one leg. Old room had lines slowly added over time. Amp was running 240 in there as well. I believe it was wired with 10G solid core cable. There was a mix of metal and "plastic" conduits and boxes in the old room. ( BTW, had serious ground loops in the old room, but the Boulder gear was fairly impervious to it. I demoed a single ended Lamm amp and it buzzed like a fiend!) Using a mix of hubbell and voodoo (cryoed hubbell outlets) in new room. Plastic plates.

So what do you think? Any ideas?

Jim

 

RE: Your thoughts...., posted on December 8, 2016 at 12:09:42
Cpk
Audiophile

Posts: 1518
Location: PA
Joined: May 13, 2005
 The conduit in not good. 12awg stranded in wall is going to sound different then solid core. Since probably 100% of power cords designed with solid core in the wall, I'd go back to that. Not a big fan of Hubbell's. Braid isn't great but less impactful then above

 

RE: Braiding the AC mains feeding a power amp., posted on December 25, 2016 at 11:50:03
gordguide
Audiophile

Posts: 302
Joined: January 20, 2002
 " ... If he does respond back and the answer is no I am going to recommend he hire an electrical for a day and just run a few new exposed Romex cables just on the floor over to his equipment. The electrician could just install some plastic outlet boxes on the ends of the Romex cables. ..."

Doesn't meet Code anywhere I'm aware of, so no Electrician would risk a fine (yes, that's what happens) to install it. So either he does it himself (carries it's own problems) or it doesn't get done that way.

I don't know what level of penalty a licensed Electrician would face, but I can tell you that a contractor we normally use forgot to take out a permit on one installation on a job with multiple installations. The fine was $2000.00

 

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