"Roger Thorpe" wrote in message
...
philcud wrote:
Just started to get an earth loop using my laptop as source connected
to amp.
just starte
get 'cricket' type sounds when the laptop is connected to power lead.
problem goes totally when i half remove the power lead,
gets unlistenable when the power lead is removed and laptop running on
battery.

only just started happening, any ideas?

Are you using a headphone output from the laptop set at very low volume?
This can quite easily give high noise from (I assume ) the power line in
the computer. the solution would be to turn up the volume on the computer
and down on the amp.
Or look for a line level output.
Or use a usb sound card.
Sorry if it's too obvious , but it's good to check the easy ones first.


The clue, I think, is in the "gets unlistenable when the power lead is
removed and laptop running on battery", yet "problem goes totally" when the
power lead outer is making contact. That suggest, IMO, that there is no
chassis connection between the laptop and the amp. As Eeyore says that could
be due to the sleeve connection on the 3.5mm jack breaking away from the
PCB, not an uncommon occurrence.

David.