I am in the UK. I want to know how to reduce hum & buzz when connecting two items together.
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I have two pieces of electronic equipment (a PC and a tape recorder) that I want to connect so that a signal from the tape recorder is fed into the PC.
However if the two earths are connected then I get a buzz and hum. This does not seem to be induced on the screened cable because if I take the line output rather than the earphone output using the same length of wire for each then the line out is clean (but too weak to use).
The PC has an earth in its mains lead. The tape recorder has only two mains wires in its mains lead with no earth.
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I am told there are adaptors I can use in series with the signal lead which will stop the buzz & hum. I believe such an adaptor isolates the two earths from one another.
An example of such a product is the Retell (model 142) Connector.
How does such a connector or adaptor work ???
Surely it's not simply a matter of cutting the earth lead such that it is no longer continuous between the tape and the PC ???