Power Cables

[Folsom]

So we know and IEC PC is down 5dB and the Shuynata is down 15dB?

We don't have actual figures. Basic twisting pair with 6 turns per foot will provide 13db, but Shunyata probably was able to get in a few more turns so I said 15db. But some Shunyata power cables are shielded, which can increase the performance to say 30db, but even as high as 70db depending entirely on what it's plugged into. You have to keep in mind however that the power conditioner may be much more effective in some different ranges than the power cable, but assuredly have decent overlap. And both are more and less effective depending on the frequency.

IEC PC could be as low as 0, 5 was probably too generous. The wires essentially run in parallel in them.

But you're missing the point by comparing the attenuation numbers, because you're overlooking the fact that they're cumulative. Nothing changes that in this example. And nothing changes that a cord with no turns per foot cannot attenuate as much as any cord with any turns per foot. So, yes, we know that the Shunyata cord will be an improvement but it's subjective as to how the audibility improve is, just like the power conditioner itself is subjective in the audible concern.

 

[Dynamix]

So we know and IEC PC is down 5dB and the Shuynata is down 15dB?

Seems more like "we" are just guessing at this point...

 

[BlueFox]

If you guys are interested in Shunyata then go to their web-site. They explain their technologies, list all their patents, and the components used in their cables. Send specific questions to customer service, and they will most likely try to answer it.

http://www.shunyata.com/

 

[Folsom]

They don't list things like attenuation for power cables. But luckily some of us know a bit about such things.

 

[BlueFox]

Ask them.

 

[Speedskater]

Shunyata Research: Bringing New Meaning to the Term Critical Performance Factors

I thought that blog was beaten to death on other forums way back in December.

 

[BE718]

We don't have actual figures. Basic twisting pair with 6 turns per foot will provide 13db, but Shunyata probably was able to get in a few more turns so I said 15db. But some Shunyata power cables are shielded, which can increase the performance to say 30db, but even as high as 70db depending entirely on what it's plugged into. You have to keep in mind however that the power conditioner may be much more effective in some different ranges than the power cable, but assuredly have decent overlap. And both are more and less effective depending on the frequency.

IEC PC could be as low as 0, 5 was probably too generous. The wires essentially run in parallel in them.

But you're missing the point by comparing the attenuation numbers, because you're overlooking the fact that they're cumulative. Nothing changes that in this example. And nothing changes that a cord with no turns per foot cannot attenuate as much as any cord with any turns per foot. So, yes, we know that the Shunyata cord will be an improvement but it's subjective as to how the audibility improve is, just like the power conditioner itself is subjective in the audible concern.

Can you show the frequency V attenuation data for these cables? Such as:





If not, why not?

 

[Folsom]

I have no idea why you're asking? The answer as stated is no. The figures are to show the relationship difference between types of cable construction. They're based on Ott's examples. The reality is it's all relative but explaining an in depth look would be ridiculous, and not understood by anyone without a background.

And again exact figures aren't relevent to the question.

 

[BE718]

I have no idea why you're asking? The answer as stated is no. The figures are to show the relationship difference between types of cable construction. They're based on Ott's examples. The reality is it's all relative but explaining an in depth look would be ridiculous, and not understood by anyone without a background.

And again exact figures aren't relevent to the question.

I am asking because this is the measurement forum.

I am asking because this is a fundamental judge of how well the cable does what is alleged to do, IIRC for which there are industry standards to test against.

As I asked, why not?

Dont confuse the benefits of a differential input / cable twisting and just cable twisting.

 

[Folsom]

I'm glad you posted more than 50/50 measurements, as they're not very practical. But yet in the case of power, engineering is more useful than test measurements due to the advserse and morphing nature of home AC.

 

[BE718]

I'm glad you posted more than 50/50 measurements, as they're not very practical. But yet in the case of power, engineering is more useful than test measurements due to the advserse and morphing nature of home AC.

Yes 50ohm measurements have limitations hence the other more demanding test cases.

I think you are going to have to explain a little further than just saying "engineering". I thought measuring actual results would be classed as engineering.

 

[Folsom]

I mean that using known information and experience provides a better approach for AC than trying to model and test a gazillion possibilities. Over the years I've seen mistakes that won't be shown from many typical tests. I guess it's somewhat aggravating because there isn't a simple answer, sadly, to most AC concerns.

Experience is the really tough one because you need cross experience with other things, too, to get some predictability for AC applications.

Maybe I'm wrong but I thought this was called the measurement based, which was implying technical information that can substitute when appropriate? If not we're going to need more than some unknown noise graph a tech is pointing to

 

[BE718]

Those arent models, they are actual measurements.

Im not sure what you are getting at here, if its that difficult why the confidence that these cables do what they claim? We have zero data in their case. Are you saying these filters dont do what they claim?

Im not sure I agree with you assertion, measurement based is just that. No problem with discussing theory, however it would be nice to have some proof of the pudding

 

[BE718]

I followed the link at the start of the thread and found the dtcd article.

http://www.theaudiobeat.com/blog/shunyata_dtcd_analyzer.htm

I was rather concerned to see that such a fundamental misunderstanding is occurring.

The current delivery capability of your mains is not dictated by the last metre of cable, it's dictated by the impedance of the entire circuit which may be hundreds of metres back to your local transformer, of which that last metre is of no significance.

The mains is varying in voltage all the time, due to loads in your house, your neighbours etc......not of course forgetting 50 or 60 times a second depending on where you live.

Where do people think the power comes from for your amp or DAC or whatever when the mains cycle is at zero volts?

A clue, it's those big cylinders on the circuit board. The instantaneous current/ power available to your circuit (amp or whatever) and voltage stability is not dependant on the mains. It's dependant on the design of the power supply in your circuit.

That they don't see the irrelevance of this test is mind boggling.........then again perhaps they do see.......

One thing these cables will be very good at however is putting strain on your equipments IEC connector

 

[Folsom]

So what do you propose makes the difference? Just noise attenuation?

I've found that 10a CMC's cannot work correctly for a device of mine that cannot use more than approximately 2.250a, it's a clear bottleneck. But consider that the device uses capacitors that charge and discharge. Their peak current to charge with a short time period can be rather large. So it comes to no surprise larger amps could have peak current at considerable levels, which could be taxing on the AC delivery. Also power cables are not solid core.

 

[BE718]

So what do you propose makes the difference? Just noise attenuation?

I've found that 10a CMC's cannot work correctly for a device of mine that cannot use more than approximately 2.250a, it's a clear bottleneck. But consider that the device uses capacitors that charge and discharge. Their peak current to charge with a short time period can be rather large. So it comes to no surprise larger amps could have peak current at considerable levels, which could be taxing on the AC delivery. Also power cables are not solid core.

The differences? What are these?

So the limitation in your house is the circuit breaker. Its part of the entire circuit I mentioned above. I dont know what you are referring to with "a device of mine that cannot use more than approximately 2.25A", it obviously uses more if it trips the breaker.

Yes of course the caps charge. However their rate of charge will be limited in the first instance by the impedance and current capability (size) of the transformer in the power supply and of course the design of the caps themselves. Oh and of course that after rectification the supply voltage is rising and falling at a rate of 100 or 120 Hz.

The point is that the last meter of mains cable isnt the limitation to this.

The relevance of solid core?

Havent got onto regulated PSUs yet.

 

[Folsom]

The CMC in that example is following a transformer. There's no circuit breaker involved. It's limited to 2A internally and the one thing outside of 250ma~. But it also has capacitors that don't have a limit for in-rush current.

Solid core carries more current.

The difference, between power cables that is audible.

 

[BE718]

The CMC in that example is following a transformer. There's no circuit breaker involved. It's limited to 2A internally and the one thing outside of 250ma~. But it also has capacitors that don't have a limit for in-rush current.

Solid core carries more current.

The difference, between power cables that is audible.

Sorry, I obviously misinterpreted. In that case I am not clear what you are referring to by CMC. Please elaborate. Sorry I am really not clear by what you mean by It's limited to 2A internally and the one thing outside of 250ma~. Whats the device, an amp?

Solid or stranded should be irrelevant. The cable should have an appropriate cross sectional area for the required current load / allowed voltage drop and heating. However it is true to say that solid will have a fractionally lower resistance, but it is hardly significant

grabbed off the internet - For example, a 12 AWG solid copper wire has a resistance of about 5.21 ohm/km compared to 5.32 ohm/km for a 12 AWG stranded wire. Yes thats a difference of 0.00011 ohms per metre.



Is there any objective evidence to show this difference?

 

[Speedskater]

I followed the link at the start of the thread and found the dtcd article.
http://www.theaudiobeat.com/blog/shunyata_dtcd_analyzer.htm
I was rather concerned to see that such a fundamental misunderstanding is occurring.
The current delivery capability of your mains is not dictated by the last metre of cable, it's dictated by the impedance of the entire circuit which may be hundreds of metres back to your local transformer, of which that last metre is of no significance.

This is all very true!
The DTCD "dynamic transient current delivery" is all rather meaningless until they test the complete system from the big power company transformer down the street to the connector on your audio component. They also claim as a virtue what others build power line filters to reduce.

 

[Speedskater]

"CMC" may mean Common Mode Choke. Not sure what is meant by limiting to 2 Amps. Maybe that's it's failure point or maybe it adds a lot to the power line source impedance.