Amp earthing

[simon]

Cheap seems popular then. Does that say something about us?

[Dave the bass]

Cheap seems popular then. Does that say something about us?

Down here in the sunny Sarf we used pure gold wire 'cos we're proper posh like.

(It's normally stolen though 'cos we're all a bit dodgy)

DTB

[pre65]

Well DTB-good job i'm an honest East Anglian (not south)

On long earth runs is there any benefit to be had using screened cable,and earthing the screen at the star end ?

Can earth cables pick up RFI (cant see why not).

[Cressy Snr]

Well DTB-good job i'm an honest East Anglian (not south)

On long earth runs is there any benefit to be had using screened cable,and earthing the screen at the star end ?

No

Can earth cables pick up RFI (cant see why not).

Yes so you need to keep the wires as short as possible. Again we are talking here about resistance. If RFI voltages meet resistance in wires they will generate currents in whatever is picking them up, so the shorter the earth wires the better.
OTOH star earthing is better at getting these currents to earth without them interfering with other parts of the circuit, so RFI may be a problem but then again it may not, it depends.

Steve

[Nick]

On long earth runs is there any benefit to be had using screened cable,and earthing the screen at the star end ?

But by doing so, you are introducing more resistance (thiner wire) and extra inductance and capacitance, whiich will preven the RFI picked up by the circiut itself from getting to earth.

The shorter the better, and thicker doesnt hurt. The use of foil fims has science behind it as well as its a lower inductance way of achieving the same cross section.

[pre65]

Hi-today i actually got round to doing the "star" earthing on the 832A and seem to have solved all my previous hum problems.

Thanks guys for the help and advice.