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Old 19th May 2005, 03:58 AM   #1
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Default Problems with OPA549/LM833 and static

I'm having problems with my subwoofer built with a bridged OPA549 and a LM833 for crosoover.

It's part of a 2.1 system rebuilt using a broken set of z-680 speakers. Ever since adding the LM3886 chips for the satellite speakers, I've been noticing the output from it a constant static sound that sounds like the input but with static in the sub, but it is only audible at lower volumes.

Is this just a sign my 100W transformers are crapping out with the load (like the other problem I have where the thing runs out of power and the 3886s start making some odd popping sound that goes away once the amp starts clipping), but I don't see how the power of a transformer would cause this odd static.

Thanks!
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Old 21st May 2005, 03:35 AM   #2
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Nobody has any ideas?

I can make a recording of the sound with my microphone tomorrow if it will help
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Old 23rd May 2005, 09:26 AM   #3
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Possibly layout problem or even passive component
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Old 26th May 2005, 03:25 AM   #4
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Thanks!

You were right, it was a component problem. One of the 0.1uf caps on the crossover PCB had lost a solid connection, so it would barely make contact and cause the sound, or not make contact at all and cause even more static.

It's 9:30 here
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Old 26th May 2005, 03:27 AM   #5
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Thanks!

You were right, it was a component problem. One of the 0.1uf caps on the crossover PCB had lost a solid connection, so it would barely make contact and cause the sound, or not make contact at all and cause even more static.

It's 9:30 here now, so I will try re-soldering that part tomorrow. Hopefully it will work!

Thanks again,
Mike
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Old 30th May 2005, 02:17 AM   #6
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That was it! thanks! Now it works perfectly,and, somehow, even the problem with the popping sound in the 3886s are gone.
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