AR11M Notebook HiFI noise with AC Power problem

[KMJP]

Having just recently purchased an AR11M I find when I plug into my HiFi from the headphone socket (not ideal - why not include AV out ?) I have no problems when running on battery but as soon as the AC power is put in there is significant noise to the Amplifier for every source selection on the Amplifier. Anyone had the same problem or has found or can suggest a solution. This is a bit of a problem for a media notebook.

Keith

[rich912]

Hi Keith and welcome to Club Vaio.

This sounds like a cable shielding problem that is causing a ‘ground loop’. Make sure that the external power supply cable to your notebook is as far away from any audio leads as possible. If this doesn’t work then investigate better quality (shielded) audio leads.

[drosca]

Hi Keith,

I had the same problem and this hum eliminator fixed it.

Dacian

[KMJP]

Thanks for your help - I'll try it out.

Keith

[KMJP]

I will try some new cables - but the FS series notebook I used before had no problems - I thought it was perhaps an eathing related problem. I'll try the cable but think the hum eliminator is probably the answer. Thanks for your help.

Keith

[KMJP]

As a further update. I purchased a set of Blue Jeans Cables LC10s which have a pretty good shielding setup. This has improved the noise problem - but is has not gone away entirely. I can't help thinking that putting the audio outputs so close to the power supply in the laptop is a foolish design move for a media level machine. Although I did connect the machine up to my creative labs speaker set (subwoofer and satellites) without any noise problem - Now I guess it is either the hum minimiser or a set of optical input DAC's to try to avoid the problems.

Keith

[PoorFool]

Kieth

Would much appreciate an update on the optical approach.

Mike

[Dekesh]

I have noticed something very interesting regarding this noise problem. I too get this noise issue when connecting my laptop to the tv (for audio, video is fine). with the ac power supply not plugged into the laptop i get no noise. as soon as i plug it in the noise is clearly evident. however if i shut the lid of the laptop i notice the noise becomes virtually gone. its still there but its much less so i guess a decently shielded cable would do the job. i think others should give it a try and see if it improves the noise problem. also could someone with a shielded audio cable give it a try and see how it helps.

[KMJP]

With the shielded cables I have, the noise disappears when I close the lid of the laptop - however this is simply because my machine hibernates when I close the lid. Though interesting effect number two is that there is a volume level on the hifi where the noise is almost negligible. I am no hifi expert but I guess there is some point of electrical balance with the system. This is my preferred method of control at the moment - although I am on the lookout for the hum eliminator still.

Keith

[Dekesh]

well the noise would go away with hibernate enabled. my laptop is set to do nothing when the lid is closed so the screen turns off when closing the lid. it appears the screen draws a lot of power and when the power supply is connected and the lid closed (i.e. screen off) then the power required by the laptop is lower and therefore also reduces noise. it sounds wierd but it does reduce the noise quite a lot.