Quote:
Originally Posted by Heatercathodeshort
You mention that when wander plugs are connected you get a hum. Is the lead screened?
Is the lead just O/C at it's end, if not what have you got connected to it? Slightly confused. John.
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For clarity:
Here a picture of the arrangement. The radio in this picture is a phonola (Italian Philips), just being used as an example. It's a little firecracker of a set with a pp el84 output stage and an ecc81 before that, and a seperate gram setting. From memory I think the gram input setting isolates the pickup from the rest of the radio
So the Bluetooth module is connected as per picture. With the Bluetooth module switched off, there's a lot of hum
Turning it on completely stops the hum. The project box by the way just contains 2 summing resistors to convert stereo to mono.
It's not a major problem as the pickup by definition need something connected to it and switched on to play through it, I was just curious about the mechanism. As others have said, it's probably just rubbish being picked up by the cabling which gets shorted out when the module is turned on. I'm sure the resistor mentioned will sort it too.
G