[Soundminded]

Not really. "zero source impedance",  "infinitely large current" and "circuit breaker" are three different things.  If a circuit has the same supply voltage at zero load and at full load it has "zero source impedance".

No that is not the definition of source impedance.  The definition is open circuit voltage divided by short circuit current. However you define "full load" voltage can be increased to compensate for voltage drop due to source impedance as load increases without changing the source impedance. Only when the load is a short circuit, an infinite load, can the source impedance be judged to be zero. This of course is an impossibility. We do however use the assumption of zero impedance at times to calculate short circuit current on the secondary windings of transformers. The actual impedance of the secondary is higher than calculated because it adds to the source impedance adjusted for the turns ratio as referenced in a previous link I gave. That means sizing circuit breakers for the calculated short circuit current will make them adequate for the slightly lower short circuit current encountered in the real world.

[Soundminded]

[quote author=

"Here's something to consider when watching electrical experts compare slide rules on audio forums:
Physicists have recently managed to transport a single particle from one vacuum sealed jar..."

Irrelevant. Power distribution is not nuclear physics. It has been well studied and understood for a very long time. Far better than is needed to get audio equipment to operate properly.


It would be fun to see you take apart the white paper on DTCD measurements which was posted on this forum. You're willing to spend hours dispensing your knowledge about decades old electrical design theory but I predict you won't stoop to the heavy labor of responding to a real current expert. I suspect you're all hat and no cattle. Explain why the DTCD white paper is "irrelevant"...and be specific by addressing lines in the paper.  Show us what you're really made of. I dare you. 

Never heard of it before this posting. I assume this is what you are referring to.

http://www.shunyata.com/content/DTCD-whitepaper.html

The flaws are obvious to anyone familiar with facilities based power distribution systems. They fall into several categories. Non real world testing, non verification of test results through measurements of load performance and double blind listening tests, equivalent results by far less expensive methods.

Shunyata's basic argument is that the electrical impedance of a power cord will affect the performance of the load, in this case a high power audio amplifier.

First the nature of the source. The test source in the DTCD has a source impedance of .0016 ohms. Much too low, far from real world applications. Why does that matter? The lower the source impedance and the larger the load the more significant the series impedance of the power cord will be. This is seen in the circuit analysis of Thevenins equivalent referenced above. There are three impedances for this analysis, the source impedance, the power cord impedance and the load impedance all in series with the ideal voltage source.

What is the source impedance in the real world? The absolute minimum legally allowed is .012 ohms. Why? Take a very close look at the circuit breakers in your panel. In the fine print it will say something like 10KAIC or 10,000 amps interrupting. This is the maximum current that circuit breaker will interrupt in a short circuit. The source impedance for this condition is calculated by dividing the open circuit voltage 120 volts by the short circuit current, 10,000 amps. That's about 8 times what Shunyata used. But in the real world that isn't even close. If you were sitting on top of a 50 KVA single phase transformer with a standard 5.75% impedance, the source could deliver no more than 3600 amps so the impedance would be three times as great. In the real world the transformer is somewhere outside your house many dozens to hundreds of feet away and is typically much smaller, say around 10 to 25 kva. The series impedance of the wire between that transformer and your wall outlet including the utility company feeders coming into your house, the contact resistance of the main and branch circuit breakers at their line and load lug connections as well as the breaker contact resistance and the series impedance of the branch circuit wiring must also be taken into consideration when calculating the source impedance for Z(i) in Thevenins theorem. Typically it will be 50 to 100 times or more than 0.0016 ohms. The measurements Shunyata made are already seen as invalid. 

The steady state load cannot be more than 12 amps for a 15 amp circuit breaker, 16 amps for a 20 amp circuit breaker. This is because the circuit breaker is rated at 80% continuous load. This is typical for most thermal magnetic breakers including QO types use in your panel (it isn't even called a panelboard by manufacturers it's so light duty, it's called a "load center.) So for a standard 15 amp wall plug (NEMA 5-20P) the load impedance can be no less than 10 ohms, 7.5 ohms if you have 20 amp circuit and a (unusual) 20 amp plug (NEMA 5-20P.)  I leave it to you to look up the resistiivity of the wires and estimate the distances to calculate the feeder and branch circuit wire impedance. Don't forget to double the number since you must take into account both the hot leg and the neutral.

I won't go into measureing the differences between amplifier performance and double blind listening tests using different power cords with real world loads and sources, that has been discussed to death.

High quality connectors like Hubbell referenced in the papwer are certainly recommended. Fortunately they are available in practically every electrical supply house in the United States and only cost about $5 to $10 each retail (much cheaper in contractor price quantities.)

Now for the equivalent methods. It is well known that conductiviity in wire is along the surface and skin effect, that is resistance to electron flow increases with frequency. The way to reduce this is to increase the surface area. One method is to use hundreds of strands of very fine wire and hope they have sufficient resistance between them that they behave as individual conductors and not as a single aggregate. This is expensive. The other way is to simply use a heavier gage wire that has a larger surface area because it has a larger diameter. This is very cheap and at least equally effective.

Bottom line, the Shunyata white paper comes to obvious conclusions in a non real world test environment whose results are repeatable using much lower cost equivalents. BTW these flaws were obvious to me within 30 seconds of reading them. Normally I deal with far more arcane problems that can require weeks or even months of calculations and analysis. 

[jaxwired]

Here's my 2 cents.  I have no idea if I need power conditioning and I don't think anybody else really knows either.  However, the only outlet near my hifi can only accomodate two plugs.  So I have to have something to plug the rest of my gear into.  So I bought a running springs haley that has six outlets.  I plug everything into except my amp which I run to the wall.  It's either this or a cheap power strip.  I think of it as an expensive power strip.  Nothing more.  If it does some good, great.  If not, it's still doing it's primary job which is to provide more outlets...

[cheap-Jack]

Hi.

I have no idea if I need power conditioning and I don't think anybody else really knows either. ..

There are tons of EMI/RFI airborne & flowed-in from the powerlines which should be stopped from invading our audio systems.

The point I want to make here is NO NEED of spending a fortune to acquire
costly brandname power conditioners unless one don't know nothing about EMI/RFI & get sorta scared by the terminology & don't mind spending big bucks to get rid of it.

(1) The first groundwork to start power conditioning, IMO, is install dedicated powerlines direct from the electric panel to the audio rig.
Dedicated powerlines will shorten the long long journey of the power supply
from the panel to the audio system by bypassing the long long loops of electrical cables inside the walls. So reducing the RF contamination of the electrical cables to the audio rig by large proportion.

(2) With dedicated powerlines terminated with dedicated wall outlets located just behind the audio rig, the demand of using costly power conditioner/filter will NOT be needed. Big money saving.

At my home, I have had 125V & 250VAC dedicated powerlines installed from the electric panel to my audio rig, terminated with dedicated wall outlets installed just behind my rig

From the dedicated wall outlets to the power strips where my gears plugged in, I installed simple RFI inline filters (10A rated, RFI insertion loss 52dB at 32MHz, made in England) each for each powerline, one for 250VAC, one for 125VAC exclusive for digital gears only (CD player & DVD-audio player), & one filter for 125VAC analogue gears only.

ALL floor running powerline cables are elevated from the floor with semi rigid
foam blocks. NO power cables & power cords are allowed to touch each other.

WARNING: NEVER plug anaolgue gears, e.g. analogue preamps, power amps etc. into power strips sharing with digital gears, e.g. CD players etc.

c-J

[Rclark]

"WARNING: NEVER plug anaolgue gears, e.g. analogue preamps, power amps etc. into power strips sharing with digital gears, e.g. CD players etc."

Why is this?

[roscoeiii]

Don't know why, but it is common for some power conditioners to have outlets that are specified for analog, digital and sometimes for amps. The APC models are one example.

[cheap-Jack]

Hi.

"WARNING: NEVER plug anaolgue gears, e.g. analogue preamps, power amps etc. into power strips sharing with digital gears, e.g. CD players etc."

Why is this?

Because any digital equipment, e.g. DVD/CD player, cellphone charger, flat screen TVs, etc etc etc, emit airborn RFI as well as discharge RFI to the powerline hooked up to it.

Sharing same power strip or even powerline means allowing RFI discharged by the digital gear into the other equipment sharing the same power pool.

I can read such RFI surge on a power strip with a DVD/CD player plugged onto it, on the screen of a brandname powerline & EMI noise analyser. No kidding, bud

c-J

[mjosef]

Short answer. YES...but only if you want your rig to sound its absolute best.

[rw@cn]

I still disconnect (via PS Audio Duet) my HDTV and cable box during listening sessions. Despite what some say the music does sound better. I tried it since I had an extra Duet it works very well for me. Cleans up the hash.

The optimum solution would be to get all of the video gear into another room, but that won't happen without a winning lottery ticket. 

[rollo]

  For me a 20 amp dedicated ciruit [ quad outlet ]. Then a PI Audio Uber Buss for power correction. Digital gear is plugged into an isolation trannie into a power strip plugged into Uber Buss. Quiet, dynamic with tight defined bass. Works for me.
 



charles

[roscoeiii]

And I imagine it has been mentioned before, but worth stating again:

If you are concerned with protecting your equipment, be sure that a power conditioned offers surge protection. Not all power conditioners do. The PI Audio Busses for example do not. They are fantastic devices, but for peace of mind I felt it was necessary to pair with something that had surge protection.

[jtwrace]

for peace of mind I felt it was necessary to pair with something that had surge protection.

And your choice was?

[cheap-Jack]

Hi.

Short answer. YES...but only if you want your rig to sound its absolute best.

Why not? Proper power fllters should not cost more than a good soundiing system.

c-J

[cheap-Jack]

Hi.

I still disconnect (via PS Audio Duet) my HDTV and cable box during listening sessions. Despite what some say the music does sound better. I tried it since I had an extra Duet it works very well for me. Cleans up the hash.

The optimum solution would be to get all of the video gear into another room, but that won't happen without a winning lottery ticket. 

Glad to hear better sound with purified power.

Don't be silly, RFI is all over the place wherever you move yr digital gears.

There is one economic & yet effective way to minimize RFI discharge into the powerlines by digital equipment, that includes mcrowaves oven, range, frige, washer etc etc which are ALL built in with digital controls.

Clamp one or even 2 RFI ferrite ring suppressors, available dirt cheap from parts shops, onto the power cord of those appliances & devices.

Besides the above, I even do the same to ALL my audio components, including my CD & DVD-audio players, needless to say.

Why? Any elecric conductors, e.g. power cords, speaker cables, interconnects, can be a damn good landing dock for airborne EMI/RFI
& short cuts for powerline RFI.

Adding the ferrite ring will effectively change or mismatch the free space-electro magnetisc fields impedance (377R) of the conductor to stop it from becoming a RFI transmitting/receiving antenna

c-J

[doug s.]

"WARNING: NEVER plug anaolgue gears, e.g. analogue preamps, power amps etc. into power strips sharing with digital gears, e.g. CD players etc."

Why is this?

remember, in a pm, i told you to plug your dac into a separate isolation transformer, and do the same w/your transport?  even if you don't plug everything into a single power strip, you will get a lower noise floor and more detail if you do this.   

doug s.

[cheap-Jack]

Hi.

.. i told you to plug your dac into a separate isolation transformer, and do the same w/your transport?

Not all "isolation transformers" are angels. Some can ruin the sound quality.
Make sure to listen critically any sound improvement after inserting a powerline isolation transformer. It may or may NOT!

I had my very bad experience by adding a custom-built 1KVA statically shielded powerline isolation transformer, built huge like a battership, with a large O/P AC voltage meter & I/P voltage tapping adjustment knob on the front panel of the steel housing. After I installed it, the music instantly sounded veiled, slowed down &  lost vatality. Totally unacceptable sonically....

NOw it is seated idling in my store room for good. What a waste of money. I don't mind at all to sell it to whoever for whatever money.

c-J

[jtwrace]

Hi.
Not all "isolation transformers" are angels. Some can ruin the sound quality.
Make sure to listen critically any sound improvement after inserting a powerline isolation transformer. It may or may NOT!

I had my very bad experience by adding a custom-built 1KVA statically shielded powerline isolation transformer, built huge like a battership, with a large O/P AC voltage meter & I/P voltage tapping adjustment knob on the front panel of the steel housing. After I installed it, the music instantly sounded veiled, slowed down &  lost vatality. Totally unacceptable sonically....

NOw it is seated idling in my store room for good. What a waste of money. I don't mind at all to sell it to whoever for whatever money.

c-J

What model / brand?

[cheap-Jack]

Hi.

What model / brand?

No brandname. A custom-built 1KVA iron inside a big steel box, professionally built by a powerline transformers specialist shop.

c-J

[doug s.]

Hi.
Not all "isolation transformers" are angels. Some can ruin the sound quality.
Make sure to listen critically any sound improvement after inserting a powerline isolation transformer. It may or may NOT!

I had my very bad experience by adding a custom-built 1KVA statically shielded powerline isolation transformer, built huge like a battership, with a large O/P AC voltage meter & I/P voltage tapping adjustment knob on the front panel of the steel housing. After I installed it, the music instantly sounded veiled, slowed down &  lost vatality. Totally unacceptable sonically....

NOw it is seated idling in my store room for good. What a waste of money. I don't mind at all to sell it to whoever for whatever money.

c-J

i have had good results using simple quality medical/lab-grade isolation transformers, that can be bought on ebay for pennies on the dollar...

doug s.

[TONEPUB]

Hi.
There are tons of EMI/RFI airborne & flowed-in from the powerlines which should be stopped from invading our audio systems.

The point I want to make here is NO NEED of spending a fortune to acquire
costly brandname power conditioners unless one don't know nothing about EMI/RFI & get sorta scared by the terminology & don't mind spending big bucks to get rid of it.

(1) The first groundwork to start power conditioning, IMO, is install dedicated powerlines direct from the electric panel to the audio rig.
Dedicated powerlines will shorten the long long journey of the power supply
from the panel to the audio system by bypassing the long long loops of electrical cables inside the walls. So reducing the RF contamination of the electrical cables to the audio rig by large proportion.

(2) With dedicated powerlines terminated with dedicated wall outlets located just behind the audio rig, the demand of using costly power conditioner/filter will NOT be needed. Big money saving.

At my home, I have had 125V & 250VAC dedicated powerlines installed from the electric panel to my audio rig, terminated with dedicated wall outlets installed just behind my rig

From the dedicated wall outlets to the power strips where my gears plugged in, I installed simple RFI inline filters (10A rated, RFI insertion loss 52dB at 32MHz, made in England) each for each powerline, one for 250VAC, one for 125VAC exclusive for digital gears only (CD player & DVD-audio player), & one filter for 125VAC analogue gears only.

ALL floor running powerline cables are elevated from the floor with semi rigid
foam blocks. NO power cables & power cords are allowed to touch each other.

WARNING: NEVER plug anaolgue gears, e.g. analogue preamps, power amps etc. into power strips sharing with digital gears, e.g. CD players etc.

c-J

Dedicated power lines don't get rid of most of the noise or the distortion present in your power, though having enough power for your amp and source components will help dynamics when you are playing loud.

Good power conditioning still makes a huge difference, sorry.

And what are analog "gears" and digital "gears"?  My system doesn't have any gears in it....