Audio interference problem.

[sandogg]

I recently replaced my PSU on my micro atx system to a 400w (from 200 w) and to add a 7950GT graphics card and second harddrive. (I run Ubuntu 8.04).
Since then I have had a strange buzzing sound coming from my PC speakers.
Since the sound does not come from any headphones I attach I guessed the problem was with the speakers and got new ones.
However the new speakers do the same...
After some playing about I find that its the USB power causing the interference (both sets of speakers are usb powered).
If I power them from the mains through an adapter there is no buzz/interference.
Unfortuntely my speakers have a buitl in webcam which I use and thus require the power from the PC over usb as thats the webcam connection too, see here
Would a shielded usb cable help or does anybody know if there is there any other workaround?
Cheers :dunno:

[Nathan H]

I honestly have no idea, If your USB cable runs straight past your normal mains connection or the PSU it might be a problem. But the speakers are most likely recieving the Signal as digital if they are also getting the power through USB. Have you tried moving the speakers from the back of the case to the front or vice/versa?

[worldwise001]

Have you tried switching back to the old graphics card with the new PSU and seeing if the sound persists? If so, that could be that your PSU is not of a decent quality; I've had computers with cheap PSUs that often cause interference to my radio when I listen to AM radio. If your computer was made within the last 4-5 years (I'm guessing that it is considering you're putting in a 7950 GT in it) then the high clock speed of the processor will cause buzzing/oscillations in the power if your PSU is not of decent quality.

Gist is: Try pulling out your recently installed hardware, test if it makes the buzzing noise, and if need be, replace your PSU with a more expensive/heavier one.

[sandogg]

Cheers for the advice.
To be clearer both sets of speakers use USB for power and a standard 3.5 cable for audio.
I have tried moving the speakers, cables around but still same problem.

It most likely is the PSU affecting things as I have read about something similar elsewhere but I will try removing the hardware (graphics card and psu) and see what happens.
But I probably won't be able to do this for another month as I am away on holiday soon.

If it does turn out to be the PSU do you guys have any idea where I can get a decent 400w MICRO-ATX psu in the u.k.
I am currently using a Colours-it branded psu from here
Most other retailers I've tried seem to sell exactly the same PSU but oem.:happysad:
Cheers

[Smith6612]

Probably the PSU as I've never heard of video cards causing problems like this unless it's something to do with a messed up fan or something. Otherwise, I've heard many power supplies that emit a high pitched noise that only I seem to be able to hear, no one else who is around can hear it though. That's the really cheap ones when the PC is not on.

[worldwise001]

It most likely is the PSU affecting things as I have read about something similar elsewhere but I will try removing the hardware (graphics card and psu) and see what happens.
But I probably won't be able to do this for another month as I am away on holiday soon.

I meant to try taking out your graphics card and hard drive, as that would isolate the problem being the PSU.

Also, if you can, see about spending more than $20 USD on a psu. Good ones are generally between $30-50 USD. Also try looking for a "brand name" psu, those generally are better than obscure ones. Or if you're at a computer store where you can lift the actual PSU in the box, heavier is better.

See about ordering from US-retailers if the shipping is not to costly. I am aware of the 17% VAT slapped on just about everything (I visited the UK a few years ago), so good luck with your testing/psu search. I have a friend in Australia who orders from the US all the time, as prices are more expensive in Australia than importing from the US with shipping and all.

Erg... this forum does not like me... I thought I hadn't posted yet...

[Nathan H]

A good place i find to get computer parts, (I live in the UK and build computers) is a company called Ebuyer. Ordered parts on friday, arrived monday, and that was free delivery. Like has been said, power supplys are not something you want to cut corners with, they can cause all kinds of trouble

[sandogg]

Cheers,
I have tried ebuyer, dabs.com, aria.co.uk, scan.co.uk, ebay etc etc
but still cannot find a good micro atx psu in the uk

Can you guys recommend any good american sites for a psu please?

[Smith6612]

www.newegg.com or www.tigerdirect.com . Go with NewEgg first, since I find them cheaper and have pretty much anything.