Mains noise, laptop to dac to amp?

[admin_exported]

Hi all

While my two sons have been home from uni for xmas i have been using their laptops (i don't own one) to listen to Spotify . I have been impressed with the range of music available and the sound quality ,however one problem i have had is excessive hissing and crackling when either laptop is connected to the mains.When you remove the psu the noise stops.- From the laptop to the Caiman is via usb.

I have a couple of question:-

1. Would this be solved using an optical lead? Unfortunately both laptops are Dell with no optical out.

2. Having a quick search on google for this problem, it would appear a 'ground loop isolator' may solve the problem.Have any of you good people used this solution?

Thanks

dave

 

[basshound]

I think an optical lead might well solve this but as the Dells have no optical out the way I`ve done it is to stream wirelessly to an Airport Express and then connect the AE via optical to my Beresford.
This works out fairly costly,around £70 for an AE if you are only going to use it during Uni holidays but if you were thinking of setting up a music network then I`d fully recommend the AE.

Don`t know about "ground loop isolators" but I`m sure someone who does will be along soon!

 

[Dan.m]

I have the exact same problem. When i connect my wirless laptop to my hifi via a 3.5mm to phono cable the 'hiss' is noticeble when the charger cable is attached to the mains. Buying a sonos system soon so i'll just put up with it for now.

 

[Anonymous]

Especially with USB ground loops may be a problem. You can try to disconnect the ground pin from your laptops power supply (there are 3 to 2 pin adaptors). Here in EU mainland most laptops do not have a ground to begin with.

 

[Anonymous]

I seem to recall a post topic on mains noise a while back where it was said that laptops were a particular issue on the mains loop itself (like fridges etc.) which would effect other components on the same power loop - so might not change with interconnect used?

I'm no expert (just relaying what I read), so please don't take it from me, but if you haven't already, you might want to have a search around the old forum posts for key words like:

Mains conditioner

Tacima

The silencer

Russ Andrews

Didn't pay too much attention myself as I don't own a lap top, sorry.

 

[PJPro]

Pete10:
......You can try to disconnect the ground pin from your laptops power supply.....

Err. That doesn't sound entirely sensible. See if you can find a USB to optical converter. Maplins used to do one.

 

[Anonymous]

Strange, isn't it? All laptops here use ungrounded euro plugs (in contrast with desktops), and are, of course, approved. And I never observed a shock (also in contrast with desktops). Is the UK power supply different? I read somewhere that the earth is used for possible Electrostatic discharges, and that there is a cap between ground and AC zero in the UK system.