Strange and annoying constant noise when laptop is plugged in on AC power

[King_Ellesar]

I have a problem, and it is a very inhibiting and irritating one...


My current setup consists of an HP laptop, firewire midi controller/audio interface, Triton Extreme keyboard, mixer, then two studio monitors. it's pretty much my dream setup, so this inhibiting problem is so frustrating! I just want to be able to play freely!

The problem comes whenever I plug in my laptop and run off of AC instead of the battery power. When plugged in, I get this really annoying sound. It isn't the sound of a steady hum, but rather it sounds as if I can hear the computer working...hard drive spinning, random beeps and boops whenever it is processing something...and it is a very low quality sound, and it just destroys any good sound I make with the setup. the sound is not present when I do not have the laptop plugged in.

I've done some research on it and it seems like others have similar problems, but I didn't really find reliable solutions. I was told a ground loop isolator would fix it, so i bought one, but it didn't help....it did fix a hum that exists with higher gains...but I think this sound of a different problem source

I've also tried having all of my equipment being powered from the same outlet-something I read from a few places, but tried it even though it sounded odd...but it didn't work anyway


I can't help but think that the problem is in some way to do with the power adapter, or the plugging in of it, the circutry of the power through the laptop that is causing this very unwanted noise. I've tried all I know, and I don't want to mess more with it based on what I've read...as with messing with power like this, things could get dangerous both for me and the equipment...

I can play for an hour or so on battery power, but I'd like to be able to run off AC so I am not limited like this!

Does anybody have experience with this? or maybe knows what I need to do? Any help would be so very much appreciated!

[Gustavo]

hmmm I understand the problem isnt any physical drive spinning or the fans, but rather the beeps and bops of ur pc.

To turn this off, go to control panel, to sounds, and choose windows with no sounds. this should get rid of all those annoying sounds and some of the internal beeps

Gus

[rutgerv]

Hi,

I think that what you hear is the result of a switch-mode power supply. This is exactly the reason why many power supplies for synths are so expensive. They are very well regulated to prevent any noise from leaking into your sound. The so called 'line noise' can come from devices outside your laptop (a fridge switching on), or can be related to parts of the laptop that suddenly require more or less current. In a way a battery is much more capable of handling this smoothly than a AC power supply.

It's hard to come up with a solution. One suggestion is to check how your interface is powered. Does it run on the fire-wire power or does it have a stand-alone power supply. If you have the option I would defintely choose the latter one because an external supply will be much cleaner.

Other than that I don't have much advise. If you still have the problems a different power supply for the laptop might help (but I'm not sure if you can get something that works with your laptop and is stabelized better).

Best,

Rutger

[King_Ellesar]

Hey thank you both for the suggestions!


Hi,

I think that what you hear is the result of a switch-mode power supply. This is exactly the reason why many power supplies for synths are so expensive. They are very well regulated to prevent any noise from leaking into your sound. The so called 'line noise' can come from devices outside your laptop (a fridge switching on), or can be related to parts of the laptop that suddenly require more or less current. In a way a battery is much more capable of handling this smoothly than a AC power supply.

It's hard to come up with a solution. One suggestion is to check how your interface is powered. Does it run on the fire-wire power or does it have a stand-alone power supply. If you have the option I would defintely choose the latter one because an external supply will be much cleaner.

Other than that I don't have much advise. If you still have the problems a different power supply for the laptop might help (but I'm not sure if you can get something that works with your laptop and is stabelized better).

Best,

Rutger


Yeah, the Firewire Interface has its own power. It's crazy how much circuitry electronic musicians have to be on top of! As if programming and the audio signal weren't enough...power issues never really entered my mind as something to be mindful of, i guess it's not as simple as "plug in everything" :P

Thanks for the help. A friend of mine said he had the same problem and that changing the laptop charger plug with a 3 prong to 2 prong converter should do the trick. I'll update after I try this, for the sake of internet knowledge and anyone else who may stumble upon this problem...

[Cary]

really short on time here but a ground loop should mostly be a steady hum, not something that changes. 3-2 prong adapter would be more of a ground loop fix (the one outlet approach is also a loop-killer).
I agree w/ Rutgerv in that you're probably picking up stray rf (noise) from the AC line through something poorly shielded inside the pc.
The only other thing I could add is to make sure there are no audio cables running parallel in close proximity to any AC lines. Ideally they should cross at right angles to minimize induced noise. Also make sure no audio cables are coiled in a loop, 'cause they can start to act like an antenna.
Keep us updated.

[hephiroth]

hey, just to chime in here, i have the SAME problem with an HP laptop...could this be an issue with the HP brand? do people with other laptops (like a mac, for example), have this problem?

i'm curious to know if you find a solution...

[Grey Loki]

Thanks for the help. A friend of mine said he had the same problem and that changing the laptop charger plug with a 3 prong to 2 prong converter should do the trick. I'll update after I try this, for the sake of internet knowledge and anyone else who may stumble upon this problem...

All that'll do is remove the earth, which you've already done with your ground loop isolator.

fwiw, I agree with rutgerv - as a result of the cost-cutting pretty much all laptops go through, one of the first things to suffer is the audio, since it's deemed less necessary - let's face it, most people will only ever use it for playback on cheap speakers. It sounds like the dodgy power is being transmitted through to your interface, which also isn't sanitising its power, resulting in that annoying 'ticking' you're hearing - switch to an external supply, and you should be alright.

[hephiroth]

fwiw, I agree with rutgerv - as a result of the cost-cutting pretty much all laptops go through, one of the first things to suffer is the audio, since it's deemed less necessary - let's face it, most people will only ever use it for playback on cheap speakers. It sounds like the dodgy power is being transmitted through to your interface, which also isn't sanitising its power, resulting in that annoying 'ticking' you're hearing - switch to an external supply, and you should be alright.

one thing to add to this, though: i get the same problem, and i use an externally powered USB-audio interface...but when i plug the laptop in, the noise happens

[King_Ellesar]

Well, I got the 3-2 prong and it actually fixed it! 5 bucks for a pack of two from RadioShack, but I think they are found all over.

I don't know why or how it worked, but it does. I had the same idea about the prong converter basically doing the same thing as the ground loop isolator, but I guess it is different.


I don't know if it's an HP problem. I don't think it is...a friend of mine with a different computer had the same issue and suggested the prong converter.


This noise happened with my USB interface too, hephiroth. You should try this converter on the laptop plug if that is what gives you noise. The ground connection is for our safety, though...but I was told that if the converted plug is plugged into a grounded power strip (i guess grounded= with the 3rd, round prong), then it is safe unless there is an uber surge from a storm that blows you away....


Thanks for the help, everybody.