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RF Interference in Speaker Cables??? (video)

tomchr

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Pretty sure that voids the warranty. :) And better make sure that hole is close to the speaker terminals or your pigtail screen termination just becomes another antenna.

Tom
 

Rick Sykora

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A small hole drilled & tapped to allow connection of a ring terminal? :)

May seem obvious, but need to make sure there is a good earth ground before you drill.

On Ghent and some of the other cases, depending on builder, you usually have to do more than just screw the back to the case bottom (where the mains ground is usually wired to the case). ;)
 

welsh

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Reading and watching this, brings back some naive audiophile memories back. I am a scientist and therefore believe in objective data and experiments. But in my early audiophiles days, I remember searching for these unobtanium speaker cables made of silver and who knows what. I actually believed it.

I'm lucky though. One day decided to by a PS audio Perfect DAC to replace my "crappy" Oppo 105. The PS audio arrived, I connected it, and was actually horrified at the sound that this thing produced. I sold it within 2 weeks of owning it. Since then, I decided to evaluate equipment based on actual data, not by cost.
By all accounts some PS Audio amplifiers are OK. The eccentric DACs, however, less so.
 

Andysu

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Here is my Snake Oil joke
 

Harmonie

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Here is my Snake Oil joke

Yeahhhh, but WHICH oil ??
Only Premium Olive first extraction by mechanical process with traditional machines comes into question.
Otherwise you can CLEARLY differentiate it !
 

Andysu

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Another guy bites the Snake Oil dust, $600 for 1 lousy meter cable. o_O and please do subscribe to him cos he says that a lot.

 

voodooless

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Another guy bites the Snake Oil dust, $600 for 1 lousy meter cable. o_O and please do subscribe to him cos he says that a lot.


:facepalm: Those speakers are "just" 1K a pair for comparison. And knowing B&W, they probably are very much non-flat and coloured. The lack of any serious reviews (meaning they actually did any measurements) is telling a lot already. Amp only has a 70 SINAD as well. I would not want that guy anywhere near a mixing table...
 

AudioSceptic

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:facepalm: Those speakers are "just" 1K a pair for comparison. And knowing B&W, they probably are very much non-flat and coloured. The lack of any serious reviews (meaning they actually did any measurements) is telling a lot already. Amp only has a 70 SINAD as well. I would not want that guy anywhere near a mixing table...
The motion sickness-inducing camera "work" tells you all you need to know about the quality of this advice.
 

RichB

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milosz

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Another guy bites the Snake Oil dust, $600 for 1 lousy meter cable. o_O and please do subscribe to him cos he says that a lot.


Who would take technical advice from a guy who wore a Harley sweatshirt and a backwards ball cap to produce a video.
 

Andysu

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Who would take technical advice from a guy who wore a Harley sweatshirt and a backwards ball cap to produce a video.
No I wouldn't. absolutely not.
 

ezra_s

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No I wouldn't. absolutely not.

But but but.. he said he and his family have a heritage of hifi or something, that he made wires with his dad, that must amount to some authority.
 

rgdawsonco

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I’m a little late to this topic, but I recall seeing video where “Danny” gleefully “shows” the differences in speakers cables by connecting them to the antenna posts on a receiver and showing the difference in signal level Picked up by the wires. He even showed how touching the regular speaker cable increase the signal level because the body is also acting as an antenna. That is when I thought, OMG, all this RF interference is running in my body and probably my eardrums, no matter what cables I use. Someone needs to invent an RF shielded suit for me to wear while listening to music, I conclude, based on what Danny showed me. Though I have been interested in Danny’s filter and driver knowledge, I stopped listening then, because I thought that was the dumbest crap I ever heard an otherwise smart person say, so I am a flat earther I guess.
 
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aerochrome2

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RF chokes can help, some are more efficient in specific frequency ranges.
No more than about 5 'windings' in chokes otherwise capacitive coupling may lower attenuation again.
I don't think a different speaker cable will help, perhaps it can when it is screened or twisted.
all one needs to do in such is a case is lower the RF entering the amplifier far enough so 'AM detection' doesn't happen. It doesn't have to be completely eliminated.

Yes, it does happen that speaker cables can pick up RF and this can lead to hum, noises, radio reception.

Relatively very, very few people will actually have an situation where this happens.

An extreme case, to be sure, but if you are **VERY** near an FM or AM station, or an amatuer radio operator, or a medical diathermy machine or an arc welder, you might well experience anything from crackling or other noises to strange hums to outright amplifier failure. RF can get into gain stages in many ways and if your audio system is really near a powerful RF source it can be the most devilish thing to cope with. RF power levels decrease as the square of the distance (in general) so if you are farther than a few hundred feet from any such source you shouldn't have any problems - with the exception of truly powerful broadcast equipment in which case a mile or more might be better.

Pick up some ferrite cores that either clamp on the speaker lines, or a "donut" ring that you loop the speaker wires through once or twice. That will help suppress RFI from hitting the amplifier's output.

Aside: For power amplifiers, the most common RFI path I have seen is through the speaker cables hitting the internal feedback and bias circuits to be rectified and re-appear as audible noise in the speakers. The output impedance of an audio amplifier is typically high at RF frequencies, not low. The input cables are usually shielded and many (most?) inputs include RFI suppression (often in the form of small capacitors if the input stage itself does not reject it).

Find out if the radio station coming through is nearby.
Disconnect all devices from the amplifier and connect 1 speaker.
Then add another speaker.
Find out if this is what's causing it if it starts to happen when connecting another device to the amp.
Maybe loan/borrow another amplifier see if that helps.
Then resort to cable clamp ferrites (with big hole so the cable can be run through a few times), locate that as close as possible to the amp output.
When that doesn't help you can put a common mode choke (2x 1uH) in series with the cable.

When that doesn't help connect 1nF capacitors in series with a 4.7 Ohm between the + output to the metal chassis and - output to the metal chassis (also when the - is connected to ground) combined with the common mode choke.
When this doesn't help use a screened cable and connect the screen to the amp chassis.
When all of this fails try to route cables and locate the amp at a different spot.
After that buy another amp, one that can be returned if that too doesn't help.

Be methodical.

I am one of the referenced few people to experience FM radio station interference with modern equipment (in an extreme manner). See this thread I posted here about a month before Amir's video: ASR - Radio interference (FM) and buzzing in speakers without input source. The thread has more details, but here is the gist:
  • I live less than a mile from a massive FM radio broadcast tower.
  • As soon as I turned on my last amp for the first time, and before I started playing any music from the actual source, you could clearly hear FM radio playing through the speakers (although one speaker was much louder than the other). Nothing in the system has an FM transmitter. Increasing the volume knob didn't really affect the volume of the interference.
  • My speaker cables are twisted (Belden 5000UE). Moving the cables in the room didn't really seem to make a difference. Neither did switching to another cable of a different length (I went from 10ft to 15ft and also tried coiling near the speaker).
  • I ended up switching from the Cambridge Audio amp to an Emotiva BasX and that appeared to fix the problem.
However, and what I haven't posted in my original thread, is that when I used the headphone jack in the Emotiva (rather than through my headphone amp) for the first time the other day, I could hear the FM radio station coming through my headphones very clearly. I assume this means that the issue isn't totally gone. I have no idea how to test/measure to see if this is still an issue with the speaker output (as well as the headphones, which is clearly audible).

In any event, I really want to avoid snake oil, but it seems like an RF / Ferrite clamp or donut is a very cheap way to possibly just take this off the table as an issue. I really don't feel like buying a new amp as it has now presented in two of them.

My questions:

1) I see literally 574 choices on https://www.mouser.com/c/passive-components/filters/ferrite-clamp-on-cores/ and more in google, which is overwhelming. @solderdude mentioned some have better results with different frequencies. Does anyone have a recommendation for something to take care of an issue FM interference, specifically to address this antenna: https://radio-locator.com/info/WIHT-FM.

2) Would I only place the chokes on the speaker cables? Would I put one on my headphone cable if that is where I am getting interference? If it is the AMP itself picking up the signal, is there another option?

Thanks so much in advance!
 

Plcamp

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I would expect most ferrite clamps to be at least noticeably effective at fm frequencies. If the source of FM carrier pickup is one particular cable, you would at least hear the difference.

If you take apart a cable tv splitter, you will sometimes find a toroid chosen to operate in exactly that frequency range.

Does the emotiva detect fm on headphones with no input cables attached? If so, then a ferrite clamp at the headphone jack might help. Maybe also on power cord. Once that is clean, add in cables one by one. You might not ever get rid of all of it.
 

solderdude

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Find a clamp ferrite that has a hole with a diameter of 4x the headphone cable.
Then, as close as possible to the plug make 3 or 4 windings through the hole.
Maybe... that could do the trick.
perhaps the radio station themselves can point you to some tricks or some knowledgeable radio amateur can help.
In such cases it will be hard to get rid of this unless you have some soldering skills and know where to strategically place some capacitors.

Changes are a tube amplifier might be immune.
 

aerochrome2

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Find a clamp ferrite that has a hole with a diameter of 4x the headphone cable.
Then, as close as possible to the plug make 3 or 4 windings through the hole.
Maybe... that could do the trick.
perhaps the radio station themselves can point you to some tricks or some knowledgeable radio amateur can help.
In such cases it will be hard to get rid of this unless you have some soldering skills and know where to strategically place some capacitors.

Changes are a tube amplifier might be immune.
Interesting on the tube amplifier. Curious as to why if you have some time (will probably be above my head).
 
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