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 Post subject: 1KHz signal
PostPosted: Nov Wed 01, 2006 4:56 am 
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Location: Zip : 80751
I need to block a 1 KHz signal from an amplifier. It seems that it really picks up on 1 khz. every time i press a button on my CD player, it nearly blows my ear drums and the speakers even with the volume all the way down!!!!!!!!! How can i fix it????

Jeremy


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 Post subject:
PostPosted: Nov Wed 01, 2006 10:26 am 
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Location: Albuquerque, NM 87123
Buy a new CD player.


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 Post subject:
PostPosted: Nov Wed 01, 2006 3:16 pm 
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Joined: Jun Thu 08, 2006 9:52 pm
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Location: Lake Lavon, Texas
1kz smack in the middle of the audio range? Although I don't have a clue at this point can you give a little more info. Is it a modulation or 60 hz hum, feed back howl, motor boat? Both channels or all five if your in 5.1? It starts when you first switch on, or to, the CD how long does it last, when, how, or does it ever stop, if at all.


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 Post subject:
PostPosted: Nov Wed 01, 2006 4:38 pm 
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Location: San Jose, CA USA
You could make a 1000 Hz notch filter to knock down the amplitude, but it will make normal audio sound a little funny. Building an op-amp based active notch filter would be the easiest.

If you have a resonance in your system at 1000 Hz, then any time that tone is produced you could get an unnaturally loud tone. If there is a resonance in your system, the first place to look would be at the speaker. Most amplifiers won't do that.

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Tom K6VL


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 Post subject:
PostPosted: Nov Wed 01, 2006 4:46 pm 
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Johnnysan said it in the least amount of appropriate words...

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Don


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 Post subject:
PostPosted: Nov Wed 01, 2006 5:26 pm 
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Location: Zip : 80751
Its a trasistor circuit, it uses th Hitachi HA 13001. It has a spike at 1KHz i'll try to find the schematic of the circuit. its a very simple little amp, just the chip and about half dozen other components.


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 Post subject:
PostPosted: Nov Wed 01, 2006 6:11 pm 
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Is the CD player a separate component or is it combined in the same cabinet (using the same power supply) as the amplifier?

Dave


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 Post subject:
PostPosted: Nov Wed 01, 2006 7:52 pm 
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Location: Zip : 80751
The CD player has its own power supply. Will a new CD player have the "Beep" when i press the button?
other than pressing the button on the CD player it sounds great.


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 Post subject:
PostPosted: Nov Wed 01, 2006 9:14 pm 
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Location: Utica, NY 13502 (USA)
What I don't understand, then, is how the beep from a stand-alone CD player gets into a separate amplifier with it's volume turned down. What happens when you remove output of the CD player from the input jacks of the amplifier? What happens when you select another input to the amplifier?

The control logic of most CD players is often determined digitally. It is possible that a bad capacitor in the power supply of the CD player could cause digital crosstalk into it's audio circuits. But you should be able to control it's volume by the amplifier's volume control.

I had this happen once when I used a remote start button whose connecting wires were running too close to an audio cable from a turntable. You could hear a 1000 hz tone when pushing the button but only if the turntable was selected on the amplifier's input selector and the volume was turned up.

Dave


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 Post subject:
PostPosted: Nov Thu 02, 2006 3:07 am 
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Maybe there's an option to disable the beep or a wire/jumper inside the CD that controls it.

-Ed


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