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Author Topic: Speaker filters.. Reduce the hiss  (Read 28914 times)
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WD5JKO
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WD5JKO


« Reply #50 on: March 07, 2010, 03:28:51 PM »


What sort of speaker are we talking about??
... a few points, the cap's effect is WRT the impedance of the speaker - it has little to do with the output impedance of the power amplifier, tube or solid state.

   Bear, The speaker is a RS 8" in a wooden sealed box with foam. I just looked at similar RS speakers on their web page:

http://support.radioshack.com/support_audio/doc15/15880.htm

    I'm not sure if mine is the same, but it is similar. The VC inductance around 1mh caught my eye. The parallel L-C resonant frequency with a 10uf cap is also 1600 hz!

    I repeated my test with and without the 10 ohm series 'R', and the 10uf across the speaker ONLY makes a difference with the resistor in place. Sorry, but the amplifier Rs does matter.

    Sooo, take a amplifier with a zero ohm Rs, put 10 ohms in series with it to the speaker, and shunt the speaker with 10uf. The R-C by itself form a 6db attenuator at 1600HZ, and the VC inductance with the 10uf have a parallel resonant point at 1600 Hz.

    All of a sudden this is not so simple.... Angry

Jim
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WBear2GCR
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Brrrr- it's cold in the shack! Fire up the BIG RIG


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« Reply #51 on: March 07, 2010, 05:58:55 PM »

sure it is simple, use an inductor! Cheesy

                _-_-bear
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_-_- bear WB2GCR                   http://www.bearlabs.com
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