Not what I meant by differential mode in this case. Differential mode != differential signaling != balanced signal. The terminology here isn't real convenient. Doesn't matter if it's a SE or balanced/differential cable. The current still returns through the ferrite, canceling the magnetizing force. SE audio interconnects are more or less the same thing that we use for RF and high speed signals. It's all coaxial, with the outer shield serving as the ground. The currents passing down the center conductor return on the shield, and the net magnetizing force is zero.
I'm not going to argue about what anyone hears or thinks they hear. What I have explained above, however, is quite easily measured on the bench.
I'm not going to argue about what anyone hears or thinks they hear. What I have explained above, however, is quite easily measured on the bench.
Sure, but seems likely the lab measurement probably neglects ground noise currents carried in the shield and associated transfer impedance coupling to center conductors. Real world versus lab conditions. Sure, the ferrite is supposed to impede that unbalanced current but its not without some price.
Oversimplified modeling is a common problem with engineers. Don't ask me how I know.
There are people here who say shielded AC power cables can't affect sound of an amplifier because the resistance of the power cable is only a small fraction of the total resistance going back to the power plant generator. And the resistance can be measured to prove it. ...Sorry, wrong model 🙁
Oversimplified modeling is a common problem with engineers. Don't ask me how I know.
There are people here who say shielded AC power cables can't affect sound of an amplifier because the resistance of the power cable is only a small fraction of the total resistance going back to the power plant generator. And the resistance can be measured to prove it. ...Sorry, wrong model 🙁
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i just bought some big boy wuerth ferrites (the white middle one in the second video thumbnail)
they cost 30 euro per piece, but i got some used for 7 euro and thought i give it a try
you can easly wrap a AC cables (3x1.5mm2) 5-6 times around it and it really does make a difference compared to your usual single wire passtrough cheap ferrites, probably because you get more effective low frequency filtering using multiturns
they cost 30 euro per piece, but i got some used for 7 euro and thought i give it a try
you can easly wrap a AC cables (3x1.5mm2) 5-6 times around it and it really does make a difference compared to your usual single wire passtrough cheap ferrites, probably because you get more effective low frequency filtering using multiturns
What would you say the difference is? Different sound, different FFT, something else?
Having had to take a piece of equipment through EMC testing, ferrites and copper tape are your friend. We kept failing radiated susceptibility tests. Mind you, the field strength was 10V/m from 100MHz to 2GHz, and our equipment had an LSK170C front end designed for low noise and we were interested in signals six standard deviations above the noise, so we were making it quite hard for ourselves. In the end, the culprit turned out to be a gap in the casing 0.1mm wide by 100mm long. A bit of copper tape over that gap stopped the 600MHz getting in. The production fix was a 20 x 20mm square of earthed copper tape inside over the sensitive wires. My ancient Beolit radio buzzed horribly if mains powered with a computer on, and the fix was a clip-on ferrite over its mains lead.
I believe it, but some other people might demand a controlled listening test to verify you weren't imagining the buzz due to expectation bias. I'm serious about that. Therefore, they would say, nobody should believe you when you say ferrites helped with the buzz, since the most likely explanation is that you were just imagining it. Even worse, if it doesn't show up well on an FFT because the noise energy is spread across multiple bins, then what? To some people that can only be proof you were only imagining a buzz.
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Nobody would ask for more proof as no extraordinary claims were made. Ferrites did what they were supposed to do: lower EMI/EMC.
Bruno Putzeys heard something like a buzz (or at least a few of his customers did, along with Lars Risbo according to some accounts). It was caused by ferrites. Bruno showed that ferrites can produce hysteresis distortion/noise. Now the whole idea is not an extraordinary claim, which it never should have been in the first place since the ferrites were doing what ferrites are naturally expected to do. Of course, some people heard the effect and other people didn't. Does each person who complained to Bruno have to submit controlled listening tests to Bruno before he will take them seriously? Didn't seem to be the case.
with the big wuerth ferrittes with 4-5 turns compared to your usual small 9mm ones?
i just confirmed by listening, so look at it how you want
i also tried MANY 9mm ones on specific cables (like 10 or such)
the one wuerth ferrite with 5 turns beated the 10x 9mm ones, while both setups definitely do something (watch the video i posted showing the difference on multiturns) i suspect that the wuerth ferrite multi turn setup has much higher attenuation at lower frequencys which might be more beneficial than filtering high frequencys as some devices might be more sensitive to it?
atleast what i gathered from the video is that "optimally" you have a multiturn core followed by one or multiple single turn ferrites to get optimum attenuation at low AND high-ish frequencys (spreading the turns apart on a multiturn ferrite also improves high frequency attenuation)
interesting, i never heared of that obvious artifacts, might have been more of a circuit/oscillation thing?
while i definitely heared the bad effects of ferrites if you use too much on ananlog interconnects (specially high frequency rolloff, i starts to sound kind of dull), i never noticed "that bad" things with ferrites on power cables, the sometimes obvious audible change because of emi/rfi reduction far outweights the possible "dynamic-reduction" or such (atleast thats my opinion)
i have eupen cables (with ferrite compound around each conductor) on my active speakers and the change was so dramatic that i stopped looking for other power cables for a while now
Bruno wrote about it at the Purifi website: https://purifi-audio.com/blog/tech-notes-1/this-thing-we-have-about-hysteresis-distortion-3 There are some animations if you click on the graphs.
A few of Bruno's words from the article:
"Hysteresis distortion isn’t something that we simply decided to big up in search of a USP. It’s very real, very different from what you’d expect and not at all subtle."
Bruno is certainly right, but you are not.
Reading carefully you wll find that he considers inductors in the signal path like transformer or series inductors.
This is a well known fact and TI has publishied a paper about distortion of different output chokes used with their class-D chips.
A ferrite clamp around some power cable is a
COMMON MODE
choke - and that means it is not inside the audio signal path.
You won't find any papers where Bruno discusses ferrite clamps
Ferrite inductor != ferrite common mode choke.
Reading carefully you wll find that he considers inductors in the signal path like transformer or series inductors.
This is a well known fact and TI has publishied a paper about distortion of different output chokes used with their class-D chips.
A ferrite clamp around some power cable is a
COMMON MODE
choke - and that means it is not inside the audio signal path.
You won't find any papers where Bruno discusses ferrite clamps
Ferrite inductor != ferrite common mode choke.
Bruno is right, and I am not wrong. Its just that when there is a problem, there is one more step in the process you are missing.
Forcing an extra noise current, say, down a shield, will flux up the common mode choke causing it produce common mode hysteresis noise/distortion. The next step to making the noise/distortion intrusive is well known. It is referred to as common-mode to differential-mode conversion. Some reference material attached for anyone not familiar with the basic physical mechanism. The first paper is from AES thus directly related to audio.
The only point here is that under some conditions hysteresis noise/distortion from common mode chokes can become audible (or otherwise problematic). That is not to say it will happen under all conditions.
Forcing an extra noise current, say, down a shield, will flux up the common mode choke causing it produce common mode hysteresis noise/distortion. The next step to making the noise/distortion intrusive is well known. It is referred to as common-mode to differential-mode conversion. Some reference material attached for anyone not familiar with the basic physical mechanism. The first paper is from AES thus directly related to audio.
The only point here is that under some conditions hysteresis noise/distortion from common mode chokes can become audible (or otherwise problematic). That is not to say it will happen under all conditions.
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So you are debating the distortion of unwanted common noise currents that by some unbalance become differential mode noise.
Personally I do not care about the distortion of noise anyway.
But anyone to his own.
Personally I do not care about the distortion of noise anyway.
But anyone to his own.
A.k.a. a slot antenna. Many people don't realize a slot is a form of tuned dipole antenna that will happily be transparent around its resonant frequencies, and as here will be leaky over a wide range of frequencies.
Count me in as being ignorant of slot antenna until you mentioned it. I'm not an RF type, you see. What amazed me was that such a narrow gap could cause so much trouble; a real learning experience. I now put self-adhesive copper tape over gaps. And ferrites over cables to tame common-mode.
this might be a strange way to look at it, but imagine a device with ground/power rail and as such they will act as "low impedance path" for RF, so the PCB/circuit inside a case is literally "sucking" RF in trough gaps right? i guess specially if the case is not low impedance enough
Its mainly the length of the gap that controls its properties, just as with a dipole antenna its mainly the length of the wire, not its thickness, that controls the properties. Nearby metal objects will have a strong effect on any antenna by coupling to the near-field and redirecting it, so there's a lot of complexity involved.