2 questions

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Mike
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2 questions

Post by Mike » Sun Jul 20, 2003 6:27 am

I have 2 questions:<p>1. I have a DVD player connected through a tube preamp through a tube amplifier. An annoying buzz is heard constantly through the speakers when listening to a CD or playing a DVD. I am assuming this is a ground loop, but how would I fix it?<p>2. I would like to have a subwoofer I built allow speaker level inputs. Assuming resistors are needed for the sound reduction, what value would be a good choice?<p>Thanks for help with either of the above questions, Mike

russlk
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Re: 2 questions

Post by russlk » Sun Jul 20, 2003 11:53 am

All your audio amp and CD player should come off the same outlet. Get a multi-outlet adapter if necessary. Sometimes two outlets on the same wall will not be daisy-chained, but will each go all the way back to the power panel with loads on the line, which causes a buzz. It is not likely that the power amp connects back to the CD player, but that could be a problem also.<p>I recommend that you feed the sub-woofer with a potentiometer and set the volume as you like it. You could measure the pot and substitute fixed resistors when the level is good.

Mike
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Re: 2 questions

Post by Mike » Sun Jul 20, 2003 7:14 pm

Russ, all of the equipment is on the same line through a surge protector. Could this problem be solved by connecting a wire from the cd player case to the preamp and amp case?<p>Thanks, Mike

russlk
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Re: 2 questions

Post by russlk » Sun Jul 20, 2003 7:47 pm

If you are using shielded audio wires, they will already be connected. If the wires are not shielded, that could be the problem.

Chris Foley
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Re: 2 questions

Post by Chris Foley » Sun Jul 20, 2003 9:20 pm

Check your assumption that it's a ground loop by unplugging the CD and shorting the input. If you've still got buzz, you might have a problem in the tube preamp/amp. Check the caps first -- if it works otherwise, hum on well-designed tube amps can be a result of dried out/hi-Z electrolytics.

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