Ah, so, it might be true. Yes, this is a powered subwoofer, which most
of the PC subwoofers are. In my case, it is the electronics inside the
box that is susceptible because the case has no shielding, it's
definitely in an RF-rich environment, and adding cores to all the wires
has had no effect at all. My cores are the correct mix for 14 MHz
signals and work well in other applications in the station. Of course, I
could go in and redesign the amplifier, lowpass and bypass it. Or, I
could reach over and turn the volume down and live with it. I was merely
pointing out that adding cores to the wires may be a solution, or it may
not - it depends on where the problem is occurring. I wasn't challenging
the advice being given, merely adding to it.
73, Duane
On Wed, 11 Aug 2004 15:19:07 -0500 "Jim Brown"
<jim@audiosystemsgroup.com> writes:
> On Wed, 11 Aug 2004 11:58:30 -0500, Duane A Calvin wrote:
>
> >And, there are some speakers that cannot be cured with ferrites
> because
> >the reception is actually happening inside the speaker.
>
> That might be true, but it also might not.
>
> First, passive loudspeakers do NOT detect RF. If the loudspeaker has
> an
> internal power amp, that power amp CAN detect the RF.
>
> Second, you may have not used the "right" ferrite, or you may have
> used too
> few, or even too many, turns.
>
> Third, the RF could, as you say, be picked up on wiring internal to
> the power
> amplifier due to its poor shielding. In my experience, that is the
> least common
> and least powerful mechanism. The more common one is antenna action
> on
> either the power leads or the signal wiring. In those instances,
> choking the
> current will generally eliminate the RFI.
>
> Jim Brown K9YC
>
>
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>
>
Duane Calvin, AC5AA
Austin, Texas
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