Eliminating noise from laptop (mac) power supply

[Duncan]

I get a really fucking annoying ground hum when my macbook power supply is connected and I'm using it for audio. Live with a mixer, dubbing tapes into 4 track etc. Total pain in the arse because my battery is shit and the computer won't run for long periods without being plugged in.
Any advice on how to deal with this small yet infuriating problem?

[dust]

try to plug your computer into a different outlet than whatever other equipment is plugged into your computer

its rarely the mac power adapter and almost always something else plugged into the computer that is also drawing power from an outlet that is responsible, in my experience

[Jaakko V.]

I'd also suggest simply trying different power outlet combinations. Also, using balanced cables and connections when possible.

[pentd]

try a D.I. box?

[Duncan]

Thanks for the replies so far. I did try plugging the charger into the second outlet in the wall. My multi way plug was connected into the other, that didn't help. I'll try putting them into completely separate wall outlets but it's not going to be practical to do this every time.

Excuse my ignorance but how will a di box help?

[pentd]

a DI box *might* help due to ground lift?

or a separate soundcard/interface?

[Duncan]

I realised today this only happens when I use the headphone output. Not an ideal situation but I do have a usb output I tend to use mostly for live things which will help with the problem but more suggestions if there are any will be appreciated. I'll look into DI boxes, thanks.

[theworldisawarfilm]

Try a DI. Honestly just a good piece of gear to have if you play live, period. Just my two cents.

[Theodore]

Have you tried to move the jack when in the audio output ? Little in and out, left and right. To see if there is a position where the noise stops. From my PC i know with time and use the stereo jacks maybe dont have good connection. In my case one channel disappears. If i pull it just a mm out or twist it, it fixes. - Internal motherboard sound chips pick up some electrical noise from PC, though in normal, no audible levels.

Other thing you could do is to open the laptop and see what's going on in this output. If everything in its place, not touch with near components. Maybe deoxit it, dont know.

[Strömkarlen]

Thanks for the replies so far. I did try plugging the charger into the second outlet in the wall. My multi way plug was connected into the other, that didn't help. I'll try putting them into completely separate wall outlets but it's not going to be practical to do this every time.

Excuse my ignorance but how will a di box help?

It needs to be a different power circuit for it to help. At our office (I work at a sound studio) our printer made a low frequency disturbance in the speakers in one of the editing rooms when I plug in it in. We had to get the power supply from a third room to get rid of it.

[l.b.]

I do have a usb output

you should probably be using a usb audio interface rather than the headphone jack pretty much all the time anyway

[Duncan]

I do have a usb output

you should probably be using a usb audio interface rather than the headphone jack pretty much all the time anyway

Why?

[l.b.]

better soundcard, multiple in's and out's, XLR, multi-channel, if you're getting unwanted noise from your laptops output why even use it? usb interface can also "go both ways" as it were, playback and recording

[Duncan]

Well there are some situations where I'd like to be able to have both options. I'm more than happy to use my interfaces for most jobs but if possible I'd like to retain the speed and simplicity of using the headphone out too. Seems better to explore potential solutions than just write off that function of my laptop.

[dodecaphonic]

I get a really fucking annoying ground hum when my macbook power supply is connected and I'm using it for audio. Live with a mixer, dubbing tapes into 4 track etc. Total pain in the arse because my battery is shit and the computer won't run for long periods without being plugged in.
Any advice on how to deal with this small yet infuriating problem?

what type of 4 track is it? and what type of mixer?

so let me get the signal path right one lead running from - MACBOOK >>into>> MIXER >>into>> 4-track to record is that right?