Speakers buzzing through laptop

[shaunj_uk]

Hi,

Not sure if anyone can help, but I have my laptop running through my Roksan K2 amplifier. I have it connected via the headphone out on the laptop into 2 rca into my amplifier. When the laptop is plugged into the mains, I can hear a hum/buzz coming through the speakers, however, it doesn’t do this when the laptop is running off the battery.

Just to make sure it wasn’t the amplifier I connected the laptop into the inputs on my dvd recorder and could hear the buzz through the television where it was playing through the dvd recorder. The strange thing is that I tried it on my old Nad c340 amplifier in another room and it didn’t seem to do it.

Can anyone help me with this problem? From what I can make out it must be the laptop.

Any help would be great.

Shaun

 

[Overdose]

It sounds like a grounding issue.

 

[shaunj_uk]

Hi,

Thanks for the reply. How would I sort this? I have seen this:

http://www.thatcable.com/product/RCA-Phono-Ground-Loop-Isolator-Hum-Noise-Filter

Am I on the right track?

Thanks

Shaun

 

[ID.]

Personally I'd look to use a DAC and kill 2 birds with one stone - Improve the sound quality and cut out the buzzing.

 

[Overdose]

It might work if it is a ground loop issue, it might not if the Roksan is simply not as good as the NAD at dealing with the noise. At that price though, it's worth a shot and if it doesn't work, you can always return it.

 

[John Duncan]

Your laptop just has a rubbish headphone socket/power supply. My Sony Vaio does the same when fed from the headphone socket on and off mains, my Macbook less so. A cheap (or expensive) USB DAC would solve the problem, or you could stream to an Airport Express which, whilst not the last word in high fidelity, is better than most laptop's audio outs.

 

[shaunj_uk]

Can I change the power supply?

 

[Overdose]

Can I change the power supply?

Hang on!

Did you not say that the problem was not evident on your NAD amp?

I would recheck this first as a form of fault finding.

Before jumping to conclusions and spending money, you need to find out exactly what the problem is.

 

[shaunj_uk]

No, it doesnt do it on the Nad C340.

 

[busb]

Shaun's hit the nail on the head (in his 2nd post). Noise from the laptop's switch-mode PSU is causing ground-based interference. I get the same problem when I connect my laptop via USB to my DAC where galvanic isolation would cure the issue.

Added:

As for not being present on the NAD doesn't mean there's an issue with the K2 but I'd swap inputs to hear if doing so makes a difference. However, I'd consider something like the Dragonfly or new Meridian DAC into the K2 if funds allow but some sort of galvanic isolation may still be needed.