BTW I agree on your other comments, though the audibility in a real world situation is questionable.
IME yes it does make difference according to source end or load end placement of the ferrite core with overall slight drooping characteristic with the filter at the source end, the essing is still evident at either end but more pronounced with the ferrite at the load end.
Richard has gone. Hope he is OK, and just tired of the trolls. His inputs and experience will be sorely missed.
Mos exc vid. The ancient Chinese curse May You Live in Interesting Times has escaped from the world of Zhang YiMou into the boring pedestrian modern First World. Surprise! We're all so deeply related that the same virus kills us all equally. Unless you're poor of course.
Goddess bless us, everyone.
Chris
Goddess bless us, everyone.
Chris
If one end of the cable (by which I mean a complete headphone cable) is floating in free space and so is the other end as would be the case with a pair of headphones plugged into a mobile phone when considering the common mode behavior of said cable, a ferrite clamped on the cable will not have any effect in suppressing common mode noise since there is no common mode current flowing in the shield or return cable.
If both ends of the cable are connected so as to create a loop, then there is the opportunity to create a common mode current and potentially a ferrite will attenuate the loop current - frequency dependent of course.
In a cable with the signals and return twisted together with a shield, JN may argue that the twisted pair signal carrying currents in the cable do not cancel completely and there is therefore some current induced in the shield, but quite how a ferrite would attenuate this in common mode is beyond me at this juncture.
B,
I don't expect a headphone cable to be shielded or even twisted.
I also don't expect any significant common mode current, although there could be some from capacitive coupling between the earphones and the users head, through the body and into the hand. Which would beg the question if this observed phenomena changes if the player is handheld, in a side pocket or in the back pocket! 🙂
I am not sure if we are actually disagreeing on anything?
I don't expect a headphone cable to be shielded or even twisted.
I also don't expect any significant common mode current, although there could be some from capacitive coupling between the earphones and the users head, through the body and into the hand. Which would beg the question if this observed phenomena changes if the player is handheld, in a side pocket or in the back pocket! 🙂
I am not sure if we are actually disagreeing on anything?
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Ah ok. We are in agreement.
We now have to convince Max Planck that it’s in his head and not in the ferrite 😉
Peace.
We now have to convince Max Planck that it’s in his head and not in the ferrite 😉
Peace.
B,
You are disregarding that the headphones are used on ones' head. Although it seems clear that some here may have rocks in theirs, we cannot rule out iron or steel bits for others. Thus I will not rule out what folks hear or think they unless of course it is that mighty voice that tells them to do evil.
Scott,
I suspect the crosstalk in a common headphone cable will be perceptable if it exceeds about 1.5% of the drivers impedance. That would put the crosstalk only 30 dB down. So with a typical headphone running above 50 ohms that would require the cable to be less than 750 milliohms total. That requires a wire gauge that has a table given resistance of less than 150 ohms per 1,000 feet. Thus a headphone cord of 32 gauge or thinner could be a problem not only for crosstalk but also for breakage.
As it is actually snowing in these parts, the devil might actually be nice skating to work today!
You are disregarding that the headphones are used on ones' head. Although it seems clear that some here may have rocks in theirs, we cannot rule out iron or steel bits for others. Thus I will not rule out what folks hear or think they unless of course it is that mighty voice that tells them to do evil.
Scott,
I suspect the crosstalk in a common headphone cable will be perceptable if it exceeds about 1.5% of the drivers impedance. That would put the crosstalk only 30 dB down. So with a typical headphone running above 50 ohms that would require the cable to be less than 750 milliohms total. That requires a wire gauge that has a table given resistance of less than 150 ohms per 1,000 feet. Thus a headphone cord of 32 gauge or thinner could be a problem not only for crosstalk but also for breakage.
As it is actually snowing in these parts, the devil might actually be nice skating to work today!
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What type do you mean? In the shared ground version isn't the ground also the shield so the effective gauge might be larger. My headphone cable is two "coax" cables with no common resistive element (and 350 Ohms).
In any case the simple crosstalk should be easily measurable.
Ed:
we are headed into a high of 86 today in Oregon.
Keep the ground water that falls, you may need it later.
Cheers
Alan
we are headed into a high of 86 today in Oregon.
Keep the ground water that falls, you may need it later.
Cheers
Alan
Ah the devil just fell.
I can't imagine any headphone wire, coax or single wire, being thin enough to matter was the point.
Actually we have four rivers here! Three well know above ground and one underground. If we run out of water, it will only be because of pollution!
We should start a list -
- Little clamp on ferrite EMI filters make a difference
- Fuses make a difference
- Skillfully placed blocks containing mu-metal make a difference
- Which AC input transformer wire you choose to connect to L or N makes a difference
- Shared or independent stereo signal ground (return) makes a difference
We could start our own "Mythbusters" show! Probably wouldnt be as exciting...
- Little clamp on ferrite EMI filters make a difference
- Fuses make a difference
- Skillfully placed blocks containing mu-metal make a difference
- Which AC input transformer wire you choose to connect to L or N makes a difference
- Shared or independent stereo signal ground (return) makes a difference
We could start our own "Mythbusters" show! Probably wouldnt be as exciting...