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radio feedback/interference/improper wire grounding

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ken84

New Member
I have a home theatre system with four speaker and a sub with built in amp. the speaker is analog, wires are hardwired in the satellite and connected to the sub with 2 ends for each speaker (one red one black). the problem is, im living in an apartment and im suffering radio feedback. I can hear radio from my speaker once i turn it on (nothing connected to the speaker, just the four satellite to the sub) so im very sure that its not the audio cable thats causing the problem, but anyway i bought a ground loop isolator and connected the audio cable to the ground loop and then connect it to my processor. I bought a couple of earth magnet and tied it on my satellite wire end, also i twisted the satellite wire with bare copper wire and connected one end of the copper wire to my heavy metal speaker stand. I nvr tried ferrite beads though since i cannot get any of them in canada :( still im suffering interference from radio, though its not very loud, but i can still hear low hissing noise. are there any better solution for my problem? ive tried fixing it for almost half a year already but still no hope! any help would be greatly appreciated, thanks.
 

panic mode

Well-Known Member
Put small capacitor parallel to the amplifier inputs (ca 100pF for example).
 

ken84

New Member
unfortunately i have no access to the amp, it is built in to the sub woofer and the amp is totally concealed somewhere in the wood....
 

Agent 009

New Member
You could try something a little bit weird: you have to shield your wires. How? Just have a outer conductor shell cover the wires (yes I know this can be tricky), but the shell will prevent any outer signal to affect the inner core of the wire. I'll think up of a way, and I'll reply soon...
 

Agent 009

New Member
You could try this: Have your wires covered with a twisted copper wiring (or any other cheaper conducting material, but copper is the optimum), then you'll have to cover this shielding with something, to look nice (I suppose that irregular twisted wires on your neat home theater system would look really awful :wink: ). You can use the stuff repairmen use for shielding the cables they've cut and then connected together. It looks like a thick empty rubber wire-shaped cylinder, that is folded onto the connection part (for your system, it's the WHOLE wires...), then proper heating flame (a cigarette lighter would be great, if not a candle) would make the big cylinder shrink to fit the inner stuff (here, the shielded wires).
 

Agent 009

New Member
Hey, I found out a better way! You could just change ALL of your wiring stuff with shielded wires. I don't know if you could get them from your local electronics store or @ what price... I'm just trying to help :). So if it works, just tell us, and if not, we could search for another way....
 

stevez

Active Member
Are the components all part of a system from a single supplier? If so, is it installed, connected, etc, per the manufacturer's instructions?

I know this seems awfully basic but in many countries equipment that is sold must meet some standards that would address this. In general the standards cover transmitted or radiated energy (intentional or otherwise) as well as a tolerance for transmitted or radiated energy. I know a lot of stuff does get sold in the US and Canada that is not compliant.

I know that this might not be the technical help that you are looking for but have you contacted the dealer or manufacturer?

Technical help that I can offer - don't forget the power supply leads. Any conductor that is connected to the system has the potential to be an antenna. Capacitors at the power supply connections, right at the amplifier, might help. Without knowing the voltage, AC or DC, it's hard to be more specific.
 

ken84

New Member
Agent 009 said:
You could try this: Have your wires covered with a twisted copper wiring (or any other cheaper conducting material, but copper is the optimum), then you'll have to cover this shielding with something, to look nice (I suppose that irregular twisted wires on your neat home theater system would look really awful :wink: ). You can use the stuff repairmen use for shielding the cables they've cut and then connected together. It looks like a thick empty rubber wire-shaped cylinder, that is folded onto the connection part (for your system, it's the WHOLE wires...), then proper heating flame (a cigarette lighter would be great, if not a candle) would make the big cylinder shrink to fit the inner stuff (here, the shielded wires).

I did have bare copper wires, and its already twisted around all my wires; however as mentioned i still get the interference, but guess what, yesterday i wrap the whole bunch of cables with aluminium tape n boo.....bye bye radio. now i have something like a big aluminium hose lol (all wires inside).

I also thought of re wiring all the wires with shielded matrial like u said, thats not relly a problem, but ive spent quite some money on fixing this prob already, so im to get it done with cheapest mean. (the speaker company is really cheap.....the speaker i ahev is the top model but they use lousy unshielded wires.....man!)



stevez said:
Are the components all part of a system from a single supplier? If so, is it installed, connected, etc, per the manufacturer's instructions?

I know this seems awfully basic but in many countries equipment that is sold must meet some standards that would address this. In general the standards cover transmitted or radiated energy (intentional or otherwise) as well as a tolerance for transmitted or radiated energy. I know a lot of stuff does get sold in the US and Canada that is not compliant.

I know that this might not be the technical help that you are looking for but have you contacted the dealer or manufacturer?

it is exactly like u said, the wires are acting like antenna, every one of them, but i find it awfully wierd, there are 4 wires, but if on of them is shielded and/or geounded properly, all others cant pick up the signal. like i said, i twisted all the wires with bare copper wires and connected them to my metal speaker stand which is used to ground it, then wrapped the wireswith aluminium tape...and the interference goes off. but 3 other wires arent properly shielded......

I have contacted the manufacturer millions of times, all they cna say is get some ferrite beads and stuck it on the wire, thats really funny, radioshack canada hasnt been carrying it for a couple of years already. I also have tried getting it from other sources but they sell in bulk..

btw, all the technician could say is.....other than ferrite beads....is to move the speaker around the room until i cant hear the interference, or "theres is nothing that u can do other than moving -- your house!"

did i mention that i also tried a 80bucks (cad) monster subwoofer powerstrip? totally no hope....

although i solved the interference....um actually its only the front channels thats been solved, i actually connectedall four speaker to the front channel only, the more bizzarre part is that anything connected to the rear channel wll pick up radio signale no matter what, I believe its somehing wrong with the built in amp, probably they tuned the frequency to some frequency thats similar to commercial radio frequency. i really hope to fix the rear channel....but i really have no idea how. Btw this is the second speaker, i exchanged one from them last tim which also had the same problem. thank you for all the replies, its cool that so many repiles in just a night :) you guys have been very helpful. but if you could solve my rear channel's super interference problem, it would be even more better :D
 

gtrdude

New Member
is it possible for you to open up the satellite speakers and replace the wire with round jacket shielded speaker wire? it shouldn't be expensive. also keep the lengths as short as possible so that they don't act as antennas to radio frequencies. some of those FM wavelengths can be as short as 1m or so.
 

stevez

Active Member
Dan's Small Parts lists all sorts of things including ferrite beads. You might also purchase a choke from Radio Shack (they used to sell them) and try that - as long as the wire size is sufficient. Send me a message if you need a better explanation.

Also note that you'll find the beads in computer power supplies and other appliances. You might check the junk pile to see if you can liberate some.
 

Agent 009

New Member
Hey, the rear channel could be just 'kaputt', and it's not giving out any output, I mean, correct output, and still the connected wires would pick up the radio interference... Now you REALLY should get those so-called technical support guys to check your internal circuitry.
 
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