[Nordkapp]

Do both. A dedicated line doesn't negate the need for power conditioners, high end outlets, power cables and ICs to reduce noise, etc.

My point was does an isolation transformer negate the need for a dedicated line?

[G Georgopoulos]

yes and no,you have to decide in terms of power,noise,etc

[jea48]

My point was does an isolation transformer negate the need for a dedicated line?

JMHO, No.

If you use a 120V to 120V 1.5Kva transformer connected to a 15 amp convenience outlet branch that may be near the middle or near the end of the branch circuit run, the money spent for the transformer would have been better spent on a 20 amp dedicated branch circuit. And that's using bare minimum #12awg wire.

 

[Folsom]

But you'd be better off with both. Well, or with something (I'm not big on isolation transformers, they're ok).

[Nordkapp]

JMHO, No.

If you use a 120V to 120V 1.5Kva transformer connected to a 15 amp convenience outlet branch that may be near the middle or near the end of the branch circuit run, the money spent for the transformer would have been better spent on a 20 amp dedicated branch circuit. And that's using bare minimum #12awg wire.

Gotcha. Makes sense.

[Nordkapp]

I own a highly regarded IT/conditioner/surge suppression unit. My SQ is satisfactory and these old ears likely could not tell the difference. I had this conversation with audiologist patient of mine, and he basically said I was nuts for buying into this stuff. He said the human ear is not able to hear things of the sort, even though we can build instruments that can measure the differences.

[Folsom]

I own a highly regarded IT/conditioner/surge suppression unit. My SQ is satisfactory and these old ears likely could not tell the difference. I had this conversation with audiologist patient of mine, and he basically said I was nuts for buying into this stuff. He said the human ear is not able to hear things of the sort, even though we can build instruments that can measure the differences.

That hardly makes sense. Our instruments tell us there's little to no difference. Our ears tell us totally differently.

He simply doesn't understand electronics. He probably erroneously believes people think they "hear" the direct noise as if it comes out the speakers - You Don't.

[FullRangeMan]

If your line have 6KW power (50amps x 120V),
after a 500W transformer your line power will be only 500W and more the distortions that transformer add.

Transformer is not a solution at all, it add a whole set of new probs to the electric mains.

[jea48]

But you'd be better off with both. Well, or with something (I'm not big on isolation transformers, they're ok).

Maybe , maybe not.

If the isolation transformer used is not big enough to supply the power, in VA, to the connected load then the sine waveform will flatten out and the result is distortion.

http://ecmweb.com/content/voltage-waveform-distortion-causes-effects-cures


 

[jea48]

Although the twisting is good, after read in Bill Whitlock paper, 12/2 and 10/2 Romex® might be better than three conductor Romex®. True you loss the twisting but you gain symmetry.

Agree.

I would clarify by saying 3 conductor with ground. There in, three is a company four is a crowd.


Also I wonder what might be going on with that unused insulated conductor that is floating above ground.   

[Speedskater]

Agree.
I would clarify by saying 3 conductor with ground. There in, three is a company four is a crowd.

Yes, with Romex® nomenclature, 14/2 is really Hot, Neutral plus Ground. So 2 means 3 conductors and 3 means 4 conductors.

Also I wonder what might be going on with that unused insulated conductor that is floating above ground.

The unused wire just makes the cable more asymmetrical.

For additional reading:

Ground Loops: The Rest of the Story
Bill Whitlock, AES Fellow  and Jamie Fox, P.E.
ABSTRACT
The mechanisms that enable so-called ground loops to cause well-known hum, buzz, and other audio system
noise problems are well known. But what causes power-line related currents to flow in signal cables in the first
place? This paper explains how magnetic induction in ordinary premises AC wiring creates the small voltage
differences normally found among system ground connections, even if “isolated” or “technical” grounding is
used. The theoretical basis is explored, experimental data shown, and an actual case history related. Little
has been written about this “elephant in the room” topic in engineering literature and apparently none in the
context of audio or video systems. It is shown that simply twisting L-N pairs in the premises wiring can
profoundly reduce system noise problems.

See page 42 of this Middle Atlantic paper:
Integrating Electronic Equipment and Power into Rack Enclosures
Optimized Power Distribution and Grounding for Audio, Video and Electronic Systems

Then the correction:
Addendum to Power Distribution White Paper

http://www.middleatlantic.com/resources/white-papers.aspx

[Early B.]

Sound quality is based, in large measure, on the quality of the power.

I have a dedicated line, but that's just the beginning. Sure, it made an audible difference, but each time I added a power component, the sound improved. I have a high end outlet, highly modded SurgeX, UberBuss, upgraded MiniBuss, Hammond choke, and high end power cords. This is a "power management system."  It's of little value to speak about a dedicated line without taking into consideration the entire system. For instance, spending money on a dedicated line that flows through $0.99 outlets and stock power cords isn't going to yield very much improvement, if any.

 

[brj]

Has anyone looked at using underground feeder cable instead of typical Romex? 

Some versions seem to use the paper dividers commonly found in Romex that proved insufficient at holding the wires equally spaced during testing, but I've seen some UF-B cable where the individual wires are all held in place by the outer formed jacket.  I'm not finding a good photo at the moment, but here's a cartoon representation:

http://www.globalindustrial.com/g/electrical/wire-cable/wire/underground-wire

This would address the issue of keeping the ground equidistant from the hot and neutral.  Not sure how well it could be twisted and have it still maintain the spacing, however, if one wanted to pursue that...

[gregfisk]

Has anyone looked at using underground feeder cable instead of typical Romex? 

Some versions seem to use the paper dividers commonly found in Romex that proved insufficient at holding the wires equally spaced during testing, but I've seen some UF-B cable where the individual wires are all held in place by the outer formed jacket.  I'm not finding a good photo at the moment, but here's a cartoon representation:

http://www.globalindustrial.com/g/electrical/wire-cable/wire/underground-wire

This would address the issue of keeping the ground equidistant from the hot and neutral.  Not sure how well it could be twisted and have it still maintain the spacing, however, if one wanted to pursue that...

You are correct that it uses the jacket to separate the wire but man I hate stripping that jacket back. It would seem when twisting it you would still retain the same distance but I'm not sure about that.

[jea48]

Has anyone looked at using underground feeder cable instead of typical Romex? 

Some versions seem to use the paper dividers commonly found in Romex that proved insufficient at holding the wires equally spaced during testing, but I've seen some UF-B cable where the individual wires are all held in place by the outer formed jacket.  I'm not finding a good photo at the moment, but here's a cartoon representation:

http://www.globalindustrial.com/g/electrical/wire-cable/wire/underground-wire

This would address the issue of keeping the ground equidistant from the hot and neutral.  Not sure how well it could be twisted and have it still maintain the spacing, however, if one wanted to pursue that...

I doubt it would be any better than NM-B, (Romex is a Trade name of).

(Speedskater first posted this about a year or two ago.)
Here is a PDF of a 2012 seminar given by Bill Whitlock, President of Jensen Transformers. Read pages 16 through 36.

Note: If you want something better than NM-B sheathed cable then use 2 wire with ground MC aluminum armor cable. (Hot, neutral, and insulated green ground. Do not use MC cable that has 2 insulated green conductors as used for isolated grounding type receptacles). Again, 3 is company, 4 is a crowd.

For what it's worth I installed two 10-2 with ground NM-B cables about 75ft each in length for my 2 channel audio system. The preamp and amp are tube.The system is dead quiet.