Your Questions: Fixing Laptop Hum When On AC Power?

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AC power hum
Last updated 3 August, 2017

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If you're plugging in to a mess of other cables and gear, try and make a clean break and distance yourself from potential causes of AC hum. Pic from: milestek
If you’re plugging in to a mess of other cables and gear, try and make a clean break and distance yourself from potential causes of AC hum. Pic from: milestek

Regular reader and DJ Big Clive asks: “Having trouble with laptop noise through my speakers when my power supply is plugged into my laptop. Thing is, if it’s on battery there is no noise. Can you help?”

Digital DJ Tips Says:

This is thankfully not as common a complaint with today’s gear as it used to be, but nonetheless it is annoying, because it’s sometimes hard, if not impossible to diagnose what exactly is causing it. Even if you can, it can be tricky to rectify.

Three things to try

Here are two things that helped for us when we had a similar problem two laptops ago, and a suggestion that we didn’t try but that may solve the issue. These ideas come in cost order, cheapest first!

  1. Try putting the power supply as far away from the laptop as you can – It’s probably the transformer that’s causing this, so if you keep the distance between that and the laptop big, it may reduce or even cure the problem. That includes keeping it away from other messy AC cables
  2. Try an alternative power supply – In my experience, power supplies can vary a lot, and a different one may not give you this problem. Worth trying out the replacement first though – you don’t want it to make things worse
  3. Try an external audio interface – I am assuming you’re using your laptop’s internal sound card for your music at the moment. Instead, you could invest in an external audio interface. This is a good investment anyway for sound quality purposes, and I’d be surprised if you had the same problem when using a sound device that isn’t actually part of your computer

Hope one of the first two helps you, and if not, why not borrow an external audio interface from a DJ friend and see if that cures it? At least that way you’ll know before shelling out the green stuff.

Have you suffered from buzz or hum when connected to AC, but not on battery power? How did you solve it? Please share your thoughts with us and try and help Clive by sharing in the comments.