John Williamson wrote:

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?

If it gets to a point where you can hear it running on just battery
power, it's not a ground loop, it's a defect inside the laptop.

Agreed.


On the other hand, if it goes away totally when you run on battery, then
you may have a power brick problem. Try another power brick if you've
got one available.

It's inherent in almost every power brick. Laptops weren't designed as
quality audio sources, whatever the marketing says.


It's *possible* your battery is defective, which is causing the power
supply on the motherboard in the laptop to become unstable, causing the
sound to chirp.

Pretty long shot but you never know. I'd lay my money more on the internal
voltage regulators if it's in that area.

Graham