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Author Topic: Laptop power supply causing hum through dj rig  (Read 5318 times)

Brian Rodgers

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Re: Laptop power supply causing hum through dj rig
« Reply #10 on: March 06, 2015, 03:43:35 pm »

How?  Through what device/cable?

Sorry for not replying earlier. Our mains are all fed from the xlr out on the mixer. Some of our subs are fed from an unbalanced RCA output to xlr and others are fed through a crossover. I am thinking that it is an issue with cabling because some of the cables are unbalanced, but it also hums in the amps that use balanced xlr.
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dick rees

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Re: Laptop power supply causing hum through dj rig
« Reply #11 on: March 06, 2015, 08:42:25 pm »

Sorry for not replying earlier. Our mains are all fed from the xlr out on the mixer. Some of our subs are fed from an unbalanced RCA output to xlr and others are fed through a crossover. I am thinking that it is an issue with cabling because some of the cables are unbalanced, but it also hums in the amps that use balanced xlr.

The question is how/through what are you connecting the computer to the mixer...
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Rob Spence

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Re: Laptop power supply causing hum through dj rig
« Reply #12 on: March 08, 2015, 04:58:48 pm »

Sorry for not replying earlier. Our mains are all fed from the xlr out on the mixer. Some of our subs are fed from an unbalanced RCA output to xlr and others are fed through a crossover. I am thinking that it is an issue with cabling because some of the cables are unbalanced, but it also hums in the amps that use balanced xlr.

So, not identical as stated in the original post.

What else is different in these identical rigs?


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Ivan Beaver

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Re: Laptop power supply causing hum through dj rig
« Reply #13 on: March 08, 2015, 05:49:07 pm »

Sorry for not replying earlier. Our mains are all fed from the xlr out on the mixer. Some of our subs are fed from an unbalanced RCA output to xlr and others are fed through a crossover. I am thinking that it is an issue with cabling because some of the cables are unbalanced, but it also hums in the amps that use balanced xlr.
A drawing of what is being used (YES brand and model numbers HELP), and how it is wired would help to get a quicker response.

Until that happens-people are just guessing at how things are hooked up.
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David Allred

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Re: Laptop power supply causing hum through dj rig
« Reply #14 on: March 16, 2015, 03:34:16 pm »

May not apply, but an optical coupler (RS-232) stopped Driverack 260 communication noise from getting into the system through the laptops USB audio signal output.

David
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Janne Paul

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Re: Laptop power supply causing hum through dj rig
« Reply #15 on: June 27, 2016, 06:03:57 pm »

This is a common issue with Windows laptops. MacBooks which are used by the deejays don't have the problem.

Possibly you can remove it with a 60hz notch filter in your DSP.


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David Buckley

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Re: Laptop power supply causing hum through dj rig
« Reply #16 on: June 28, 2016, 12:38:02 am »

These are your laptops?  Easily solved: Don't buy laptops with a ground connection.
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Mark Dawson

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Re: Laptop power supply causing hum through dj rig
« Reply #17 on: June 28, 2016, 07:30:19 am »

Chop the earth pin off your laptop power lead.  Lots of power supplies link AC earth to DC negative, hence the laptop chassis. This basically creates an antenna surrounding hard disks, high frequency processors.  So yeah chop the earth off. Not really a problem on a double insulated supply.


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dick rees

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Re: Laptop power supply causing hum through dj rig
« Reply #18 on: June 28, 2016, 08:36:01 am »

Chop the earth pin off your laptop power lead.  Lots of power supplies link AC earth to DC negative, hence the laptop chassis. This basically creates an antenna surrounding hard disks, high frequency processors.  So yeah chop the earth off. Not really a problem on a double insulated supply.


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Nope.  Bad to do, irresponsible to suggest.

OP has not seen fit to reply with requested information in the last 10 weeks. Perhaps just ignoring the problem made it go away...
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David Allred

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Re: Laptop power supply causing hum through dj rig
« Reply #19 on: June 28, 2016, 10:13:06 am »

Nope.  Bad to do, irresponsible to suggest.

OP has not seen fit to reply with requested information in the last 10 weeks. Perhaps just ignoring the problem made it go away...

Neither of my laptops have 3 pin ac.  I didn't know they made them that way.
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