Karaoke Forums

anyone ever have a problem with laptop hum through your sytem when running your laptop with the power cord, not off of batteries? running my laptop into a karaoke mixer, then into a mackie mixing board, then to amp. and get a hum, only when i use the power cord> using battery power i don't not get a hum. any suggestions on how to fix?

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do a search on the site for a "hum eliminator"... there's been some discussion about this here before!

Yes, it is a common problem and I myself have to deal with it.

The easiest way is to lift the ground from the laptop where it plugs into the wall outlet. How do you do that? Simple, just use a 3 prong to 2 prong adapter that you can find at Walmart or any hardware store.

Be advised however that even this step may not resolve all noise coming from your laptop power supply....Some cheap-o laptop power supplies exhibit very poor voltage regulation and noise isolation, so you may still hear a little hiss when the music source goes quiet.

If you have purchased a laptop designed for multimedia/pro audio stage/studio purposes then there shouldn't be a problem. Most of us however don't need to spend that kind of money for KJ/DJ use.

The other option is to carry spare batteries where you would need to monitor battery condition and be ready to swap as needed.....Then you either need to go to wall power while swapping batteries or reboot and restart all programs after effecting the battery swap.

If you want lots more info and other possible fixes, then Google key words "laptop hum".

that's true about the battery problem. A friend of mine runs MTU Hoster, and she'd get the hum, unless she ran off a battery. Finally found that she could hook up that hum eliminator I was talking about, and that solved some of the problem.

I have it too with a desktop... comes from poor grounding at the venue I'm at. Even going USB out, there's still a tiny hum along with the audio signal.

My next experiment is to try the eliminator and see if it resolves the issue!

Hum, along with all other unwanted noise including hiss is usually attributed to not just one, but several sources. So address unwanted noise as a war that will include several battles where each will involve a different tactic, but where all of the battles are winable.

As soon as you start interconnecting more than one piece of equipment you invite unwanted noise.

The answer is to become smart on the cause of noise and noise prevention. It's one thing to try to eliminate noise, it's another to prevent it.....Best solution is to prevent it.

Start with proper patch cables and gear selection. Never buy a piece of gear that does not incorporate fully balanced TRS and/or XLR connection jacks then always use fully balanced (shielded)patch cables to connect everything. Always try to plug everything into the same wall circuit and learn about proper gain structure.

Even the best matched and connected system can generate noise if you exceed the noise floor and dynamic range of your equipment, so really study your equipment specs and tweek the gain from mic to speakers.

Whin my system is idle, I can crank my mixer to unity all the way across the board with amps at full tilt and then hold my ear next to my mains and not hear even the slightest hum or hiss....That's sweet!

Also while this method is good for a "temporary" fix, is also very dangerous as it can open yourself up to electricution since the Earth ground is no longer connected & if any spike did happen to go through the system, it will hit anyone holding a mic.

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Yep, but only the laptop ground would be lifted in this case.....My laptop is 100 percent plastic on the outside so it's 100 percent safe.

purchased a "ground loop isolating cable" at radio shack & this got rid of 95% of the hum, thx, for the help.

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ANYTHING IS POSSIBLE!!