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Sujet: Interference

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I recently bought a new laptop to replace my aging one and also a set of Mackie Thump active speakers, unfortunately its impossible to use the two together due to the massive amount of electrical interference noise when the laptop is being run with the mains lead plugged in. I use a Pioneer ergo controller and with this being bus powered ie uses the laptop power, it gives me around two hours of playing time, obviously no good for a for or five hour job. This was never an issue with the old laptop and wondering if anyone else as had a similar problem or any thoughts on the matter. Thanks
Dave
 
Posté Sun 17 Nov 13 @ 4:47 am
If you are using the headphone output on the laptop you'll need a direct box. to convert the signal for the Thumps. This is especially true if your new laptop is a Mac.
Also the thumps are great starter speakers and as such they use a single input for both mic and line levels. Make sure you don't have the speaker level knob turned up too high.
 
kjdj99 wrote :
you'll need a direct box. to convert the signal


No, the signal doesn't need "converting".

What he needs is a GLI (ground loop isolator) that connects in line between the Ergo output and the speakers, to remove the noise.

Can be had for around £8 from Maplin.
 
Thanks for the advice, the setup I use is the Ergo connected to the laptop via the supplied USB cable, the Ergo into a mixer, then mixer into the speakers, also try not to have volume (on the speakers) more than 50% ie 12 0'clock, and use the volume controls on the ergo and mixer, I'll look into a GLI
 
we had the same issue on a sony laptop.. the powersupply had ground issue.. you can by or get ground isolator..
 
Ground is most likely the problem. Have the same prob with one of my laptops.
 
I have a ground isolater on order, will let you know how it goes
 
Problem solved, bought a DTI (Dual Transfer/Isolator) made ART on Ebay for around £40, it reduced the noise by about 90%, not perfect but now an acceptable level. It has multiple inputs/outputs ie 1/4inch jack, XLR and RCA. would now happily use the new laptop on a job, would thoroughly recommend
 
Well done. That ART unit's just a posh version of a GLI, so same difference.
 
I would suggest using the XLR outputs from the ART if you are not already using them. This helps by sending the signal in a balanced configuration and reduces noise pickup. If you are then you can sometimes reduce any ground loop noise further buy ensuring that the screen pin on the XLR cable is only connected at the speaker end.

You can "lift" the screen wire "braided or thicker wire" from pin 1 inside the XLR connector at the end you plug into the ART. Ensure that the wire is insulated once it has been disconnected and re assemble the XLR connector.

Many of these units have a "Ground Lift" switch built in. If so the above is not required. just ensure that the switch is set to "Lift".

cheers

Daz
 
Thanks for your help guys and for the further suggestions. I looked at the GLI from Maplins but it seemed more automotive than Pro audio, so I took a punt with the ART unit, rather more expensive but it worked and that's the main thing. This was the back up laptop, so much happier having a back up system that works now!
 
New update, I tried the XLR in and out, it reduced the interference by about another 90%. its now just a quiet hiss. I cant believe the difference, again thanks for the advice, great bit of kit, would recommend it to anyone having interference or static problems
 


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