开云体育

Hi.

First of all, all audio wiring should use shielded wires.

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I had a look at the BITX circuit and also at the LM386 data sheet that I am attaching.

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I noticed that the volume control slider goes to the non-inverting input pin 3 of the LM386 directly without an isolating capacitor.

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This means that not only will the volume control go scratchy over time as it has a dc voltage between the slider and earth, but also that the internal biasing of the LM386 will be upset depending on the setting of the volume control.

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I suggest that you put an isolating capacitor from the slider of the volume control to pin 3 of the LM386.

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You can use any available value that you have, such as 100nf, 1μf , 10μf etc with the + side going to pin 3. The lower value will simply reduce the low frequencies.

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You can put this capacitor on the back of the volume control

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Have a go and please report back to the group.

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Regards

lawrence