Ferromagnetic materials in audio connectors

[SSS]

Read the post and maybe some around it. It was a materials issue, not the board.

Don't have the patience to read all comments. When will have time and the gear hopefully then I will try to measure the effect of steel as conductor. Unfortunately I have no AP analyzer, so I will try it with my soundcards. And need a power amp with extreme low distortion.

 

[Rick Sykora]

Cross-posting from another thread…

@Rick Sykora did a deeper dive into this issue and if he is willing may be able to explain better what is happening when using a ferrous material.

Did not delve into the physics of it, but some smart folks at Purifi claim that hysteresis distortion can occur when iron is in the signal path. The distortion also reminded me of what happens with an oxidized contact. Ran this by some experienced electrical engineers I know and they said a good solder connection should resolve. I tried this with the steel tab and it did not fix.

…since it was mentioned, felt it worth pointing out that this iron-related distortion is infinitesimal in comparison to the level of distortion from any conventional speaker driver. When cost is not a major factor, prefer to see better measuring parts used. Doing so does not mean there is always an audible improvement attained (as some would like to claim).

 

[Kip]

Is this more usage of electrical theory in Radio frequencies miss-applied to the human hearing spectrum ?
Shouldn't any of this be discussed using known equations of electrical theory, namely the ones that include the considered frequency in them ?
In my opinion this initiative has been also adopted by people marketing USB reclockers.

 

[DonH56]

Is this more usage of electrical theory in Radio frequencies miss-applied to the human hearing spectrum ?
Shouldn't any of this be discussed using known equations of electrical theory, namely the ones that include the considered frequency in them ?
In my opinion this initiative has been also adopted by people marketing USB reclockers.

No, though the effect is likely inaudible unless there is just flat-out bad contact, but it is readily measurable at audio frequencies. The ferroelectric effect is well-known and well described in electrical theory, though probably more at a grad level in college or specialized senior courses. Applications of the effect itself, like Hall effect sensors, are useful at very low frequencies (to DC for current probes, for example). Just general issues with dissimilar materials are common in places like power delivery (50/60 Hz AC wall power, e.g. the service box where Al wires come in and Cu goes out) and other applications.

This is a much different issue than USB reclockers, special audio Ethernet switches, super-duper clocks, and the like.

 

[Kip]

No, though the effect is likely inaudible unless there is just flat-out bad contact, but it is readily measurable at audio frequencies. The ferroelectric effect is well-known and well described in electrical theory, though probably more at a grad level in college or specialized senior courses. Applications of the effect itself, like Hall effect sensors, are useful at very low frequencies (to DC for current probes, for example). Just general issues with dissimilar materials are common in places like power delivery (50/60 Hz AC wall power, e.g. the service box where Al wires come in and Cu goes out) and other applications.

This is a much different issue than USB reclockers, special audio Ethernet switches, super-duper clocks, and the like.

It's the topical differences I am referring to.
The scale of effect in RF frequencies versus human audible frequencies show a miss-application of theory.
In very much the same way, audio characteristic are miss-applied to packet based digital communication.

 

[DonH56]

It's the topical differences I am referring to.
The scale of effect in RF frequencies versus human audible frequencies show a miss-application of theory.
In very much the same way, audio characteristic are miss-applied to packet based digital communication.

For the ferromagnetic effect?

 

[Kip]

For the ferromagnetic effect?

Yes, even the skin effect. No purpose in discussing it without equational backdrop.

 

[DonH56]

Yes, even the skin effect. No purpose in discussing it without equational backdrop.

OK, just checking. Skin effect is different (and also inapplicable to audio); I have an article about that here on ASR, but don't think I actually gave the equation even in simplified form -- most of my "technical" articles here assume a non-engineer target audience so do not go all that deeply into the theory. It does have a pretty picture, though.

 

[MaxwellsEq]

Yes, even the skin effect. No purpose in discussing it without equational backdrop.

I think I get what you mean. If I were to paraphrase your point: "the formulae for ferromagnetic effect and skin effect are easily discoverable in college-level textbooks and online technical resources, therefore any discussion in a community like ASR can be linked to references which are a confirmation"

So, it's easy to demonstrate that skin effect is irrelevant at audio frequencies, whilst the ferromagnetic effect is relevant at audio frequencies but may not be audible. And this should be linked to trustworthy technical references.

Part of the problem is there are many members and guests inexperienced at dealing with college-level mathematics, so narratives are often needed to soften the learning!

 

[Kip]

I think I get what you mean. If I were to paraphrase your point: "the formulae for ferromagnetic effect and skin effect are easily discoverable in college-level textbooks and online technical resources, therefore any discussion in a community like ASR can be linked to references which are a confirmation"

So, it's easy to demonstrate that skin effect is irrelevant at audio frequencies, whilst the ferromagnetic effect is relevant at audio frequencies but may not be audible. And this should be linked to trustworthy technical references.

Part of the problem is there are many members and guests inexperienced at dealing with college-level mathematics, so narratives are often needed to soften the learning!

Has anyone presented an equation that defines effect of ferrous metals in audio ?

I would like to add the frequency units in this formula are MHz

 

[NTK]

Non-problem for audio, but passive intermodulation distortion (PIM) can be problematic at wireless communications frequencies. (For some reason, the US 3M site didn't work.)

https://www.3m.com.my/3M/en_MY/communications-infrastructure-my/resources/blog/full-story/?storyid=33e225e9-2163-480a-a47b-2b3f255ba9d8

4.8: Passive Intermodulation Distortion

eng.libretexts.org