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Post by brubacca on Nov 17, 2015 10:34:08 GMT -5
I have a strange issue going on and I would like some help in resolving. Next to my neighborhood is a radio tower. When I try to listen to my headphones I can hear the radio station. As soon as I plug in I get that sound. My configuration is laptop, meridian explorer, headphones. I have had this problem with multiple headphones and multiple amps/devices.
Yhe crazy part is when I run the laptop off of the battery I do not get the radio sound. It is only when I plug the laptop / or other devices into the wall.
Any suggestions? ( other than sell my house and move)
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Post by yves on Nov 17, 2015 11:08:15 GMT -5
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Post by brubacca on Nov 17, 2015 13:31:36 GMT -5
Still can hear radio tower through my CMX-2.
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Post by yves on Nov 17, 2015 13:47:48 GMT -5
Between the CMX-2 and the affected equipment, are you using power cables that are double shielded?
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Post by brubacca on Nov 17, 2015 13:56:37 GMT -5
I have been running the test on two different setups.
1- Dell Laptop using their supplied power supply. I have no idea as to the shielding
2- Old Squeezebox 3 using the power supply included with the Squeezebox.
In both cases i can't tell if they are shielded. I also don't have the opportunity to use a different cable.
I see your point that that cables themselves could be picking up the signal.
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Post by vneal on Nov 17, 2015 14:02:41 GMT -5
THEY are listening to you
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hemster
Global Moderator 
Particle Manufacturer
...still listening... still watching
Posts: 51,921
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Post by hemster on Nov 17, 2015 14:45:45 GMT -5
Most likely the radio signal is via induction through the power cable for the laptop. Try a power cable with an RF choke on the cable. These chokes look like a "lump" on the cable, somewhere near the end that goes into the laptop. You can buy the kind that snaps on the existing cable (left pic) or get a new cable that has one built in (right pic with the cylindrical object circled).   Edit: This also applies to any other items plugged into the laptop... e.g. USB drives etc. Remove each in turn to eliminate the offending cable. The remedy is the same - fix an RF choke or change the cable. |
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Post by brubacca on Nov 17, 2015 15:42:42 GMT -5
I have a few of those chokes in the basement. I'll try them, if I can find them
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klinemj
Emo VIPs 
Honorary Emofest Scribe
Posts: 14,776
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Post by klinemj on Nov 17, 2015 16:23:51 GMT -5
I had this problem with my TT way back in college. I moved into an apartment at the tallest point in Cincinnati, and there used to be a very powerful radio broadcast (in Spanish) that emitted from somewhere in town. My TT (which was using a low output MC cart) started picking it up when I moved into that apartment. Of course, in those days, there was no such thing as CD's or streaming, so I had to live with the issue until I moved out. Luckily, I was just there for 3 months while on a short term internship. And, I could only hear it if the amp was on and no music was playing...just a faint Spanish voice coming through the speakers. If I really cranked the volume, I could not hear the Spanish voices over the tunes...so, I listened really loud that summer.
Good luck solving your issue!
Mark
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djreef
Sensei
Thoroughly enjoying my Schiit
Posts: 353
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Post by djreef on Dec 5, 2015 18:47:36 GMT -5
I have a few of those chokes in the basement. I'll try them, if I can find them Did they work? DJ |
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Post by brubacca on Dec 5, 2015 18:53:36 GMT -5
I found them, but have yet to try. Possibly tomorrow.
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Post by 405x5 on Dec 5, 2015 19:33:59 GMT -5
I have a strange issue going on and I would like some help in resolving. Next to my neighborhood is a radio tower. When I try to listen to my headphones I can hear the radio station. As soon as I plug in I get that sound. My configuration is laptop, meridian explorer, headphones. I have had this problem with multiple headphones and multiple amps/devices. Yhe crazy part is when I run the laptop off of the battery I do not get the radio sound. It is only when I plug the laptop / or other devices into the wall. Any suggestions? ( other than sell my house and move) Not strange and you are not alone..... I also live under a radio tower I call "Kevins Tower". He's an old motorcycle buddy of mine who climbed the damm thing to the top when he was a teenager (don't tell!). Your battery "unplugs" you from some of the interference no doubt. You will need to keep experimenting with different gear that better rejects outside interference. I can only tell you what solved my problem....Emotiva's XMC-1 (thank goodness) With my former processor, I would get some interference (background you could hear a touch of that broadcast from the tower.) Once the XMC came in, the radio interference went away, forever. Thank You Tennessee! Bill |
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Post by lionear on Dec 6, 2015 13:03:37 GMT -5
I have a feeling the sound is being created by the headphones and your input stage. I doubt that it's a power cable or mains filtering issue. It's also not about whether the wire between headphone and amp is shielded.
I had that issue with an Audio Research SP-9 preamp (on phono). I was told by William Zane Johnson himself (shameless name drop) that there are two capacitors that should be filtering out that sort of interference in the preamp. (To be fair, that SP-9 had some unauthorized mods, so I'm not suggesting that all SP-9's have this issue.) I soon changed preamp (and kept everything else the same), and I didn't hear the radio anymore.
You hear it with two different amps. Do you hear it if you changed headphone brand?
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Post by audiobill on Dec 6, 2015 14:53:04 GMT -5
Headphones and cartridges each have coils which are inductors.
In some churches, they have induction based hearing aids - same principle may be operating here.
Try putting your head in a shielded box or helmet while listening.....
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Post by brubacca on Dec 7, 2015 14:49:15 GMT -5
Just wanted to report back on this.. No joy on the Chokes.
The power supply cable already had one, so I added a second one. My usb cable is a Audioquest Cinnamon so it is of decent quality, but I added a choke core. Also I added one to my headphones. I have tried two different types of headphones, both Sennheiser and AKG. I would say that the sound is there with or without the power supply connected. It is very faint with the computer being plugged into power, but still there. Once I plug the computer in the sound is amplified.
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DYohn
Emo VIPs
Posts: 18,366
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Post by DYohn on Dec 7, 2015 14:54:57 GMT -5
Are you using XLR ICs somewhere in your signal chain?
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Post by Axis on Dec 7, 2015 15:38:16 GMT -5
If you can get a hold of Pete he might just still have his radio interference filter and sell it to you. Never know.  |
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Post by brubacca on Dec 7, 2015 16:17:12 GMT -5
No XLR.
My "system" is Dell Laptop, usb cable, Meridian Explorer, Headphone (AKG K550). I am sitting in the same spot with the headphones pkuggedinto my iPad and no Radio interference. I have also tried a Squeezebox at this location.
So Squeezebox or PC- hear the radio tower
iPad- Silence.
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Post by audiobill on Dec 7, 2015 16:41:55 GMT -5
Googl e this, lots of posts.....
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ilok
Minor Hero
Posts: 64 
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Post by ilok on Dec 9, 2015 18:00:25 GMT -5
Move, EMF exposure is a one way ticket to getting cancer.
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