Re: How isolate two earths on electronic equipment?

On Thu, 23 Mar 2006 05:44:14 GMT, Sammy <no-one@xxxxxxxxxxxx> wrote:

I am in the UK. I want to know how to reduce hum & buzz when
connecting two items together.

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).
So it is unlikely to be a ground loop - probably the headphone output amp has
hum on it anyway - you should be using the line-out.

The PC has an earth in its mains lead. The tape recorder has only
two mains wires in its mains lead with no earth.

So why does the subject ask about isolating two earths?
If /both/ pieces of equipment were earthed then you /might/ need to do something
about the possible ground loop when adding a third connection between them.

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.

You only have one earth.
<snip>


Geo
.

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