andrewg112 Posted November 8, 2009 Share Posted November 8, 2009 Hi,Weve got a cd running from a laptop into a new surround soud system but any time the jack is plugged into the laptop we get a constant buzz. Its reasonably loud and is not the normal amp buzzing quiet sound. There are suggestons that it might be the earth loop.... Any Ideas very welcome! Thanks,Andy :blink: Link to comment Share on other sites More sharing options...
DanHerbert Posted November 8, 2009 Share Posted November 8, 2009 Chances are it's the power supply! Try unplugging it and seeing if it stops! Link to comment Share on other sites More sharing options...
andrewg112 Posted November 8, 2009 Author Share Posted November 8, 2009 yes, the noise stops with the power off. but I cant turn the power off and have the music playing at the same time...HELP!!! Link to comment Share on other sites More sharing options...
johnnie Posted November 8, 2009 Share Posted November 8, 2009 It's probably a ground loop hum, caused as said above by the laptop's power supply. Do you have anything else plugged into the laptop, for example a USB mouse? If not, sometimes a fix can be plugging in a USB device Link to comment Share on other sites More sharing options...
Shez Posted November 8, 2009 Share Posted November 8, 2009 yes, the noise stops with the power off. but I cant turn the power off and have the music playing at the same time... I think Dan was suggesting unplugging the laptop's PSU, not turning the laptop off. If it can reliably run on batteries for however long you need to play the CD for, that's the easiest solution. (Although surely a CD player would be even easier?!) As others have said, it's almost certainly a ground loop. This is very common with laptops; a quick search of this forum should turn up dozens of threads with the various ways around it. Link to comment Share on other sites More sharing options...
osal Posted November 8, 2009 Share Posted November 8, 2009 something like this can help http://www.maplin.co.uk/Module.aspx?ModuleNo=33172 Link to comment Share on other sites More sharing options...
ben todman Posted November 8, 2009 Share Posted November 8, 2009 I have had this problem many times and have worked out that laptops with the 3 pin cable causes an earth loop whereas the power adaptors with the figure 8 2pin lead don't have this problem , use a ground loop issolator and your problem will be sorted. :blink: http://www.m-99.co.uk/Car_Audio/Noise_Suppressor/ground_loop_isolator.jpg Link to comment Share on other sites More sharing options...
dbuckley Posted November 8, 2009 Share Posted November 8, 2009 Bet the laptop is a Dell. I rescued one out of a bin recently and tried touse it for sound at a rehearsal. Bzzzzzzzt! The next rehearsal I had a stereo DI box... Link to comment Share on other sites More sharing options...
paulears Posted November 9, 2009 Share Posted November 9, 2009 My Dell is exactly the same. A DI box works fine to remove it. As long as my dell says there is 90 mins of battery life or more left, it will run for ten minutes, so ok for emergencies. Sadly - we do this topic every couple of months, but Dell never seem to change - even when the new PSUs appear on new models. Link to comment Share on other sites More sharing options...
andrewg112 Posted November 9, 2009 Author Share Posted November 9, 2009 Laptops HP... but it also does the same with Acer. Im not sure how the system is all put together, as I had nothing to do with it but I think one of these will fit somewhere. is should even though I have a jack to put the sound through the amp... right?? Thanks,Andy Link to comment Share on other sites More sharing options...
Just Some Bloke Posted November 9, 2009 Share Posted November 9, 2009 Maplins sell adaptors as well. Just get phono-jack or jack-phono adaptors as required. BTW my laptop is the same and it's Toshiba! Link to comment Share on other sites More sharing options...
osal Posted November 9, 2009 Share Posted November 9, 2009 I think it dose it on most laptops its to do with the dc plug from the power supply using - as a earth same as cars electrics thats why you find alot of these filters in the car section Link to comment Share on other sites More sharing options...
J Pearce Posted November 9, 2009 Share Posted November 9, 2009 My (ancient) IBM is quiet as a mouse, not even graphics card noise :) [/smug grin] Link to comment Share on other sites More sharing options...
johnnyguitar Posted November 10, 2009 Share Posted November 10, 2009 I've seen a few power supplies branded 'Kensington' (I think Misco, Maplin and Tescos sell them amongst others) and it has a figure 8 connection to the power, ie the ground pin isn't connected. That should get rid of the hum. I had the same problem and, as was mentioned a bit further up, I used a DI with a ground lift to cure the problem. Link to comment Share on other sites More sharing options...
Swizzuk Posted November 14, 2009 Share Posted November 14, 2009 something like this can help http://www.maplin.co.uk/Module.aspx?ModuleNo=33172 I went an acquired one of these today to avoid noise from my (Dell) laptop. I can say, best thing I now have in my kit bag. Nice clean sound from the laptop and not having to worry about unplugging it. Excellent suggestion. Link to comment Share on other sites More sharing options...
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