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Speaker static and interference. Any advice appreciated!

Malamute01

Novice Member
Hi there

My son has just bought some KRK Rokit studio monitors as he's really into mixing and creating music.

Each speaker (or monitor) has its own mains power supply. The speakers are plugged into the standard green connector on the back of his PC using a mini jack. The mini jack is connected to the speakers using RCA cables.

The problem: he is getting huge amounts of interference through the speakers when he moves or scrolls the mouse. I'm pretty sure noises from the hard drive are being picked up too!

So, I have tried using some TRS leads with a mini jack (the speakers have RCA, TRS and XLR connection slots). Same problem with reasonably expensive TRS leads.

So I then bought an external USB sound card . . .

http://www.amazon.co.uk/gp/product/B000KW2YEI?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00

And plugged the speakers into this and then plugged the card into the PC via a USB cable (bypassing the motherboard's soundcard completely). But the problem remains. Tons of static through the speakers.

I'm beginning to run out of ideas (and cash is not limitless!) other than trying a ground loop isolator. Is this the next logical step?

I think that's the problem because there is no interference at all when he plugs the speakers into headphones, an iPhone or when he runs them through a laptop as long as there's no mains power connected. As soon as I plug in the mains power to the laptop the interference returns immediately.

The only other advice I saw on YouTube was to use European two-pin power leads on the speakers and then plug these into UK adapters before connecting them to the mains. But, as I'm not an electrician, I'm a little reluctant to use wiring designed for a completely different electric system.

If anyone has any bright ideas/suggestions I would be most grateful as I'm beginning to exhaust my troubleshooting abilities and I'm nowhere near solving the problem.

Many thanks for reading!
 

Malamute01

Novice Member
Hi there

If this helps anyone then great.

I've been on lots of forums and, generally speaking, on most occasions I tend to get more back than I put in. Some great people out there.

So maybe time I should reverse the equation if it helps anyone.

It was a ground loop problem.

I plugged the monitors into a ground loop isolator and then into the sound card. Interference disappeared immediately (pretty sure the TRS cables helped rather than using RCA cables and suspect the XLR connections may be even better).

Now I have two KRK Rokit 6 studio-quality monitors with nothing but a little floor noise and, as this really helpful article explained, you can't run high sensitivity speakers like these with no noise from the subwoofers or tweeters.

System Noise

So, if anyone posts a problem like mine in the near future please share the above. It may help them enormously and save them hours messing about with their PC audio settings etc.

Many thanks
 

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