I'm hearing the radio in my computer's speakers, how to stop this?

[Bricolo]

Hi all,


This is a problem I've got since I bought these speakers. Now I'm seriously thinking about opening them, and trying to fix the internal amplifier. But how?

This seems strange, but the problem only happens at the evening and the night, not during the day.
It also only happens when the house's TV antenna is connected to the computer's TV tuner card.


I precise that this only happens with the speakers, the problem comes from them. With the headphones on the computer, I hear no noise. With another set of speakers, no noise too.
And I haven't the schematic for the amplifier. But maybe this problem is well known.



Thank you for your help

[Hybrid fourdoor]

Interesting, I know when someone is about to call my Nextel, because about 2 seconds before the phone rings, my left computer speaker starts crackling. I just cough it up to speakers that are ampified and only cost $9 at the store, simply not being the best.

[Bricolo]

I assume that a nextel is a mobile phone
this is quite normal, it will also do this on much more expensive audio stuff, and if you put it near a tv or monitor you'll see even worse effects

[johnnyx]

I had this problem years ago with CB Radio breakthrough. At 27MHz, the feedback loop was inoperative, so the speaker leads acted as the antenna. Non - linearities in the amplifier ( at 27MHz ) demodulated the carrier to leave the audio. I cured this problem by wrapping the speaker leads ( both wires together ) around a ferrite rod, of the type used for MW antenna. This made the RF signals cancel.

I suggest that you try a similar approach with yours. Get a ferrite rod or ring core and wrap the input lead to the speakers around several times, so that the shortest length is to the amplifier. Some computer keyboard or monitor leads have these ferrite cores around them to reduce EMI, you may be able to use one of those, but it means breaking one open. Use one on each cable, unless you find that one is sufficient.

Hope this helps.

[Bricolo]

I'll try this

so, no mods inside the amp?

[johnnyx]

Originally posted by Bricolo

so, no mods inside the amp?

It's probably not worth the trouble.
Try to work out how the RF is getting in, you could add filters at that point - but what values to avoid affecting the sound? Try the ferrite slugs and go from there, and include the TV downlead in your investigation.
It might help if you knew the radio frequency, then you'd know what frequency to filter out.
Good luck

[Bricolo]

I'm not sure but I think the frequency changes
sometimes I can hear an english radio, sometimes a french one and even a german one

[TeePee]

Have you tried muting the line in channel or microphone which carries audio from your tuner card to your soundcard?

[Bricolo]

yes
with everything muted the problem is still here
it's from the speakers, not the computer

[Bricolo]

Hi all,

I tried something 5 minutes ago:
a ferrite core around the cable connecting the computer to the speakers (like johnnix said). I made 3 or 4 turns.


The radio is gone