more fundamentalism

[BerylliumDust]

This thread split off from this one:

https://www.audio-forums.com/as-rediect/showthread.php?t=6837

It's inevitable, I suppose, but someone had to ask: did you null test or otherwise measure the performance of these cables?

No. But someone else did and I know they are of very, very low capacity: 6 pF/m. I also know they have a central insulating spacer between the cores in order to keep this low capacity unirform through out the whole lenght of the cable, by ensuring a constant width between the cores.

I know they are single solid core so that the radiated magnetic field, generated by the varying current flow within the conductor, is completely predictable and unirform and so it is the induced currents that counteract the original signal and cause distortion.

I know these are the fundamental aspects from the amplifier/cable interacting point of view.

And finally, my ear just confirms this...

 

[michaelab]

BD, you just cut and pasted that from the DNM website. There's no evidence that any of that stuff about radiated magnetic fields actually makes any difference (measurable or otherwise). I lost a lot of respect for DNM when I saw that they claim that DNM cables (speakers and ICs) are directional. Puts the rest of their claims straight into the bogus pseudo-science bin IMO.

FWIW I've now tried DNM speaker cable and ICs and noticed no difference to my existing cables

Michael.

 

[BerylliumDust]

BD, you just cut and pasted that from the DNM website.

No I didn't. Show me where they talk about the importance of low capacity cables.

There's no evidence that any of that stuff about radiated magnetic fields actually makes any difference (measurable or otherwise).

You couldn't be wronger. One very important pratical effect is the generation of eddy currents. These occur whenever alternating currents flow through conductors. When the current alters in direction there are emfs set up, and within the conductor the emfs will induce eddy currents that counteract that change. Thus in the AC case, eddy currents within the conductor tend to limit the current to a skin at the surface of the metal; if the current is limited to the outer skin of the conductor, the magnetic field within the body of the conductor is zero.

The degree of current concentration at the surface increases with the rate of current (music signals) variation.

All these holds true only for a single solid core conductor. When you have stranded conductors the described effect is shared by all conductors and in that case not only you'll have eddy currents within each conductor but also eddy currents circulating between conductors. The (time related) distortion caused by the eddy-current effect is thus magnified.

The resistivity of metals can be measured using the eddy-current effect. The material to be tested is placed in the magnetic field of an external coil. Another coil is placed closely around the material, which connects to a oscilloscope. The measurement is made by sunddenly reducing the externally applied field by turning off the current in the external coil. When the magnetic field within the metal material is suddenly reduced to zero by opening the switch, eddy currents are produce within it. The eddy currents, as they die out, produce an additional emf which is picked up by the coil surrounding the material and examined as a function of time by means of the oscilloscope. The rate at which the current dies down can be determined and from this the resistivity can be found.

I lost a lot of respect for DNM when I saw that they claim that DNM cables (speakers and ICs) are directional. Puts the rest of their claims straight into the bogus pseudo-science bin IMO.

I don't know where you saw that ridiculous claim, but if that is true, it doesn't invalidate, at all, what I've just said.

FWIW I've now tried DNM speaker cable and ICs and noticed no difference to my existing cables .
Michael.

That we'll see when you come to my house... I think your system isn't transparent enough and the great "culprits" are the transformers in your volume control...

 

[michaelab]

Vasco, there's no doubt that the phenonmenon of eddy currents exists but there's no evidence that it has any significant effect in audio cables at audio frequencies.

That "ridiculous claim" about DNM cables being directional is on the little leaflet that comes with their interconnects. It says "DNM Reson interconnect cable is directional - signal runs with print."

I think your system isn't transparent enough and the great "culprits" are the transformers in your volume control...

Here we go, the old "your system isn't transparent enough" argument where no cable differences are heard . It's bullshit I'm afraid. First of all, if the differences we're talking about require some amazing super transparent system to be able to hear them then they must be extremely subtle indeed. So subtle perhaps that they don't exist at all . Secondly, my TVC preamp (and others like it) are fairly universally regarded as amongst the most transparent you can get. Thirdly, you seem to attribute every perceived failing in my system to TVCs just because you've heard TD say he doesn't like transformers. These TVCs are a good deal more transparent than anything else I've heard. You'll no doubt claim that they introduce phase shifts. Well, they don't. These transformers have been specially made to ensure no phase shifts and a completely flat response within the audio band

You're all into accuracy and measurement etc so why don't you measure the DNM cables vs. other ones? Why, does the whol measurement philosophy go out of the window when it comes to cables?

Michael.

 

[BerylliumDust]

Vasco, there's no doubt that the phenonmenon of eddy currents exists but there's no evidence that it has any significant effect in audio cables at audio frequencies.

Michael,

Forget about audio frequecies, the eddy-effect is a TIME related distortion which is far more important to the ear than the frequecy domain.

Just think about this, how can we recognize a friend's voice through the phone so easily?

That "ridiculous claim" about DNM cables being directional is on the little leaflet that comes with their interconnects. It says "DNM Reson interconnect cable is directional - signal runs with print."

RIDICULOUS!!!

Here we go, the old "your system isn't transparent enough" argument where no cable differences are heard . It's bullshit I'm afraid. First of all, if the differences we're talking about require some amazing super transparent system to be able to hear them then they must be extremely subtle indeed. So subtle perhaps that they don't exist at all .

Why not the reverse? Your system is so "coloured" that you cannot hear any reasonable difference between cables.

Secondly, my TVC preamp (and others like it) are fairly universally regarded as amongst the most transparent you can get.

That only the null test can tell...

Thirdly, you seem to attribute every perceived failing in my system to TVCs just because you've heard TD say he doesn't like transformers.

If I am worried with induced eddy currents within a single wire, just imagine what happens within transformers when placed in the signal path...

These TVCs are a good deal more transparent than anything else I've heard. You'll no doubt claim that they introduce phase shifts. Well, they don't. These transformers have been specially made to ensure no phase shifts and a completely flat response within the audio band

Michael, don't be so upset the null test will tell you...

You're all into accuracy and measurement etc so why don't you measure the DNM cables vs. other ones? Why, does the whol measurement philosophy go out of the window when it comes to cables?

Michael.

No it doesn't. When we null test an amp connected to speakers, we are null testing the amplifier/cable/speaker interaction. If we only change between cables we can test for the difference. Bring your cables with you and we'll test it.

 

[michaelab]

So, are you saying there's no time related distortion in the phone system? Go and read the thread about Ohm's Acoustic Law and then come back to me about time distortion.

You're basing your answers on the DNM promotional material and some other stuff you've read on the web. As I said before, the fact that DNM claim their cables are directional puts all their other claims in a different and rather less believable light.

Anyway, this thread was about MA GR 20 mods. Re-wiring the speaker internally is likely to have the least impact (if any). Much better to do the cap changes that Robbo suggested.

Michael.

 

[BerylliumDust]

Quote:
Originally Posted by michaelab
So, are you saying there's no time related distortion in the phone system? Go and read the thread about Ohm's Acoustic Law and then come back to me about time distortion.


Michael,

All I am saying is that in a phone system you have 2kHz bandwidth and still you can clearly identify the voice (timbre) of a friend. That's how important the frequency domain is...

Quote:
Originally Posted by michaelab
You're basing your answers on the DNM promotional material and some other stuff you've read on the web. As I said before, the fact that DNM claim their cables are directional puts all their other claims in a different and rather less believable light.


Once more you are very wrong. I've studied all these and I'm just learning how to apply that knowledge.

Quote:
Originally Posted by michaelab
Anyway, this thread was about MA GR 20 mods. Re-wiring the speaker internally is likely to have the least impact (if any). Much better to do the cap changes that Robbo suggested.

Michael.


How do you know that? Have you ever changed your speakers caps or cables?

 

[michaelab]

This is a pointless discussion as it's impossible to argue with a fundamentalist, especially a fundamentalist who doesn't even follow his own rules. You can't simultaneously be a measurement freak and a cable believer . That eddy current stuff in relation to cables is just the same pseudo science techno babble bullshit as skin effect and all the other crap the cable companies come out with.

And now you're saying the frequency domain is not important...I'm sure I can arrange a telephone effect 2kHz bandwidth filter for your system.

Michael.

 

[BerylliumDust]

This is a pointless discussion as it's impossible to argue with a fundamentalist, especially a fundamentalist who doesn't even follow his own rules. You can't simultaneously be a measurement freak and a cable believer .

At least you could wait until we've tested the cables before being so radical...

That eddy current stuff in relation to cables is just the same pseudo science techno babble bullshit as skin effect and all the other crap the cable companies come out with.

Eddy currents are parisitic currents that oppose to signal variations, as much as the magnitude of those variations, thus they distort the signal.

Oh yeah, it's also the end of the discussion - enjoy talking to yourself

Michael.

I don't need to dicuss when I can measure it...

 

[BerylliumDust]

And now you're saying the frequency domain is not important...I'm sure I can arrange a telephone effect 2kHz bandwidth filter for your system.

Michael.

No Michael. All I am saying is that the ear is far more sensible to time domain distortions than to the frequency ones.

 

[Robbo]

NB. To all objectivists and sceptics, please lets not ruin Taz's thread with a discussion of the merits or otherwise of bybees, or indeed cables.

I really do despair of this forum sometimes

 

[michaelab]

Robbo - I've split this "discussion" into a separate thread.

 

[Chea Johndle]

I'm lovin' it.....


Regards

 

[michaelab]

This thread...or McDonalds?

Michael.

 

[BerylliumDust]

Michael,

I think you are not being completely fair here... creating a new thread that I have not started. But I really don't care...

The only thing I don't quite understand is why you don't wait till we measure things...

Anyway, why do cables make difference?

1) There's nothing like no cable. Unfortunately we must use them...

2) Do you ever ask to yourselfs why Naim uses a low capacity speaker cable (they have a central insulating spacer between the cores)?

I tell you why... because Naim amplifiers do have low frequency compensation, so a low capacity load is needed in order to guarantee the necessary amplifier stability by keeping a safe phase margin for higher frequency signals within the amplifier feedback loop. Capacity loads introduce phase rotations that can cause instability and drive the amplifier to oscillate (the negative feedback becomes positive).

3) Do you ever ask to yourselfs why Naim uses DIN plug cables?

I can tell you that the reason is eddy-current related...

PS: Naim knows how to make real dynamic music... that's why they are known for the PRAT thing.

 

[blakeaudio]

:bs: Yawn.... :SLEEP:

 

[BerylliumDust]

At least you could tell us why...

 

[sideshowbob]

2) Do you ever ask to yourselfs why Naim uses a low capacity speaker cable (they have a central insulating spacer between the cores)?

Because Naim amps have no Zobel network. Which makes them very much the exception rather than the rule.

-- Ian

 

[michaelab]

BD, as I said, I'm ignoring this pointless debate. I'm only replying to answer your question about the thread split which was because this pointless debate was ruining the original thread which was about some speaker mods, not about some pointless discussion about eddy currents

Michael.

 

[BerylliumDust]

Because Naim amps have no Zobel network. Which makes them very much the exception rather than the rule.

-- Ian

Ian,

Naim amps do have Zobel networks which are used to provide final stability against very, very high frequency (RF) oscillations.

What Naim amps don't have and that other amps have are output inductors which are used to maintain amplifier stability under all conditions. Naim amps rely on cables low capacity for that since they have low frequency compenstion. It is this that helps Naim amps in being so dynamical real.

The output inductors found in the vast majority of the other amplifiers, (Rotel is another exception), slow down the signal transients because of eddy-current effect within the coil.

That's why Naim (and also Rotel) is so famous for the PRAT thing... there's no music (or accuracy) without PRAT!