RT2000i, picking up radio

brody05

Hi all,
Heres a strange one, I have some RT2000i in the rear, both running of straightwire speaker cable, currently without RCA connections to the subs, just running speaker cable with jumpers in place.
Well, one of the speakers subs are periodically picking up radio station and amplifying through subs, I know it is the amp in the speaker because I changed the speaker from one side to the other and it is still doing it and without the main amp (AVCA1se) being on at all, then if I give the sub amp a bit of a bang it stops, go figure, is there a simple fix for this and has anyone heard of it happening before.
any help greatly appreciated...

[Deleted User]

Hello,
The first step in figuring out an RF (radio frequency) problem is to determine how it is getting into the speaker's bass amplifier. Try removing the speaker wire that connects to this speaker from the back of your receiver. See if the RF level changes or goes away completely. Then disconnect the speaker wire from the back of the speaker and determine what happens to the RF level. Let me know what you find.
Regards, Ken

brody05

Hello Ken,
Thankyou for your help with this. I did as you said and the signal stops when the cable (plugs) are removed, started again when plugged back in and it stopped before I had a chance to go any further.
I am using banana plugs and have them going into the top half of the binding posts. Why would giving it a bit of a hit stop it??? if it goes away with removing the cable, sorry for the questions, just intrigued, never come across this before.
Cheers
Brody

[Deleted User]

Hello Brody,
I'm going to assume you mean when the speaker wires are removed from the back of the speakers, correct? And not from the receiver? If so, this would indicate that the speaker wire is acting as the RF antenna, picking up the signal and giving it to the speaker's bass amplifier where it gets amplified and you hear it. A couple of things to try:
1). Try removing the speaker wire from the back of the speaker's cabinet and put some twists on the wire. Sometimes twisting a wire conductor several times reduces the reception area of the wire and is enough to eliminate getting RF. If this doesn't work then:
2). if possible reposition the speakers in the room. For example, lets say your speakers are near the north wall of the room and the receiver is on the west wall. This means your speaker wires are running from west to north. The incoming radio signal is being picked up by this west to north "antenna", the speaker wire. Just like when you turn a television rabbit ears to control reception you could do the same thing with the speaker wire. If you moved the speakers to the east wall and the receiver to the north wall this would create a different positioning of the speaker wire, hopefully decreasing the strength of the RF signal.
3). If that's not possible go to a shielded connection to the bass amplifier. If your receiver has both right and left front channel pre-amp outputs you could remove the binding post jumper plates, on the rear of the speakers, and use a shielded RCA cable to go from the receiver's pre-amp outputs to the line level inputs on the bass amplifier. If your receiver doesn't have pre-amp outputs, but it does have a sub-out connection try using this connection to just that speaker. In other words, leave the speaker wire connection to the speaker that is not getting the RF, but remove the binding post jumper plate on the speaker that is getting the RF and use a shielded RCA cable from the receiver's sub-out to the line level input on this speaker.
I hope this gives you some useful information.
Regards, Ken

F1nut

Buy better cables.

brody05

Thanks for the help. I will play around over the next few days, I dont understand though how it is only in the one speaker and when I changed the speaker to the other side the noise went with it, I did not change the cable, just the speaker, and why does it go away when I give the amp plate a bit of a hit if it is only the cable, I agree with the cable or banana plugs playing a role in somehow getting the rf signal but wonder about why it has taken 5 years to come in, I haven't moved, havent changed cables or amps and have had the speakers where they are without trouble up until a month or so ago.

Regarding the 'buy better cable', it is not a cheap cable at $25 a meter and 12 meters a side to the rear I don't think spending more would be warrented, it is silver coated and sheilded.

Will give you an update of how I get on over the next week or so.

F1nut

Ah, it is sheilded......sorry I didn't think it was. That's a real strange one you have there.

[Deleted User]

Hello,
It is possible there is a faulty ground at the amplifier's speaker connections. If you want to send the bass amplifier to me at Polk Audio, 5601 Metro Drive, Baltimore, MD. 21215 attention: Ken (be sure to include the "attention: Ken" on the outside of the box). I'll certainly be happy to examine the amplifier.
Regards, Ken

brody05

Hi Ken,
I would but I think the freight from New Zealand would be a bit expensive,haha, they are still under warrenty but if I can easily fix it myself I would be happy to, if it is the ground it would be quite easy to fix???? I could just take the amp out and drop it in here for repair but with intermittant problems I find they often dont get found and sent back unfixed.
Thanks again for your time and help. Polk No 1....

brody05

PS....
Strange yes, dodododo welcome to the twilight zone, maybe those aliens are trying to make contact again........

Hey, BTW, well done on the olympics medal haul, we got three gold so far, yeah....

PolkWannabie

Originally posted by brody05
... welcome to the twilight zone, maybe those aliens are trying to make contact again ...

Maybe you need a tin foil hat for 2000i's

brody05

laughed out loud with that one, great sense of humour Rick.

Silver does look great against black though........

Maybe a new design feature for Polk Audio, what do you reckon Ken????

gidrah

It might be a faulty cable. Try switching one for the other and see if it persists. Remove any loops in the excess. If the problem remains on that channel it might be the speaker. Then try swapping speakers. If it remains but swaps sides it might be the speaker or you receiver or pre/pro. If it remains in the same spot (with different speaker and cable) look to see what is near that speaker. Is there any wiring (i.e. cable connection box, phone line, etc) near this spot that might be causing it?


I had a similar problem before with one of my rear. Even while listening to 2-ch all of a sudden we could hear what sounded like a cell phone or 2-way radio. We've since moved, changed electronics, and don't even use the rears. While I didn't find the cause, I can say that this happened to me with unamplified speakers.

Nice rears.:eek:

brody05

Hi there,
Thanks for the input. As above I tried moving the speaker from one side to the other which in turn meant I was using the other cable and the problem went with the speaker, I can only guess as to why it is happening with the cable plugged in is somehow the banana plugs and cable are creating some kind of loop with the hardware of the amp, hence the reason it stops when removing the cable, the hitting it causing it to stop is intriguing and maybe something loose on the inside such as the ground or something, I am only guessing and will pull the amp out and have a look in my next day off but from memory they have a plastic sheild over the inside which may inhibit access, I cant remember whether that can be removed or not, if I run into trouble will hand over to the 'proffessionals' as it is still under warrenty.

Great rears they are, lots of noticeable bass from the rear in movies. I reckon every channel should have a sub in an ideal world.

Cheers
Brody:)

brody05

OK, I have had a play with the inside of the amp on the speaker in concern.
Ken, is it possible that it has something to do with the power part of it, there was three wires going into some upright 'pins', marked AC5, GND and AC, I am guessing this has something to do with the power supply, but the AC was very close to the GND and I know ground loops can create humming but can it produce RF signals too? Anyway I trimmed the end of the AC wire where it treminates on the 'pins' and gave some clearance between it and the GND, so far so good, no signal but that could just be coincidental, it was sporatic in the past and unpredictable, if I hear it again I will know that wasn't the problem, but with those almost touching and the fact that giving the amp a bit of a hit resulting with the signal going away in the past could explain it.