Ferrite Cores

NickM · 24 Feb 2011 at 22:26

Got a Panasonic plasma which came with some ferrite cores. Manual says to put them on the input cables but don't really see the need at the moment.

I do however get interference between my desk lamp and hifi amp/speakers. If I turn the light on/off while the amp is on then it makes an annoying buzz on the speakers. Would these ferrite cores help prevent that? If so where would be the best place to put them; the power strip cable, the desk lamp power cable, or the speaker cable?

Thanks

Al-Ectrician · 24 Feb 2011 at 22:33

I would loop them through the speaker cables, maybe 3 times.

See if it cuts out your interference.

NickM · 25 Feb 2011 at 21:56

By that do you mean coil the speaker cable 3 times and put the ferrite core around all 3?

PhillyDee · 25 Feb 2011 at 21:58

Feed the cable through the core 3 times in the same direction. Looping it around the core.

You may have an earth loop though.

bitslice · 27 Feb 2011 at 19:51

Al-Ectrician said:
I would loop them through the speaker cables, maybe 3 times.

That's really not going to help

The inteference is at the signal/mains end, trying to stop it at the speaker end is like holding back the waves. Think about it, the interference has been picked up and it's then being amplified before it even gets to the speakers - ferrites don't actually have any effect at audio frequencies, only at RF

Start with the power strip and add one to the lamp power cord,
possibly to any phono leads as well.
if possible move the lamp and amplifier power feeds to different wall sockets