feedback by my power supply?

[amble]

i need your advice technology buffs:

i get this weird feedback when i run my laptop via power supply. steady static plus stuff like harddisk working is hearable. it also drops out a short time when i close a program, then it starts again.

i've run it through my external soundcard and interal one and it's both the same. also tried disabeling the internal one, did all the diagnosis testing and whatnot. nothing helped.

it does run totaly fine when i unplug the power supply and use the battery. makes me think it must be the power thing but i'm not all sure. anyone ever had something like this? could it be anything else, motherboard failure maybe?

[bob]

theres a thread about this before I think, there are some kind of ground plugs you can get but it seems with some lappys you can never get around it.
its somnething to do with the power supply

[love_tempo]

Bob has a better memory than me, I think he's right about this being discussed before Can't remember what the best solution was, but I think I remember people talking about lifting the ground on the lappie PSU which I definitely do not recommend doing.

What is your soundcard connected to, a mixer?

[love_tempo]

If you move the audio cables and power cables around (try parallel, perpicular and far away) does the sound change?

[amble]

soundcard is connected to an amp, i've tried it with different amps too and it's the same everywhere.

moving power/audio cables around doesn't help, i get some crackles and pops when i rattle on the firewire-cable.

anyways thanks for the help you twos, i still got waranty though so no big problem. gonna give them a call today and get sorted

[M H]

I think the proper way to sort this problem out is to use a DI box is it not? Removing the earth from the plug is the bodge way to do it, but I'm not sure how advisable this is.. probably not very due to electric shock risk..
check these links:
http://ask.metafilter.com/mefi/20028
http://www.adkproaudio.com/groundhum.cfm

[bob]

i tried a di actually and it didn't seem to totally solve it, it did help though. from what I remember it is just a problem with some power supplies and theres no def fix... I could be wrong tho

[amble]

thanks for the links Mark, interesting read. i don't think i'll need a DI though cos it's not a groundloop i'm facing - i'm pretty sure now the power supply is fucked. i was using it with no problems for a long time. plus i recently had my graphics card changed cos it was dead, i'm thinking i may got a power peak once that affected both, not sure if this is reasonable.
anyway technican will be on my doorstep monday and hopefully solve the case. thumbs up

[AVX23]

there's a really easy way to sort this out which is tried, tested and cheap.

Take a 4 way or even just an extension lead, whatever - you only need one socket.

Remove the earth connection and seal it up.

Plug your laptop into that.

No more mains hum.

It's the earth that causes it.

You can also buy boxes as per above which will 'clean' the power source.

I normally run said extention into a surge protect device in case I fry my laptop, I've never had a problem with this yet and I've used in clubs, fields, warehouses and the worst place of all......my hovel.

are you saying one day this was fine, next it was not ? could be maybe you've never noticed it before perhaps ?

[amble]

Originally Posted by AVX23

are you saying one day this was fine, next it was not ? could be maybe you've never noticed it before perhaps ?

yep was working absolutely fine for one and a half year. and the noise it does now is hardly to be overheard.

as i said its like all the signals inside the computer (harddisk/processor working) are amplified and given out to the audio card (internal and extern one), and that only happens when i run it on power supply. not on battery.
someone in the forum M H posted had the same problem and said this couldn't be solved by using DI or something.

also i don't think i want to fuck around with cutting apart wires and stuff, it worked before so they should make it work again. electricity is my friend as long as it stays inside the cable, but i ain't looking for a 220 volt slap.

[AVX23]

hmm yeah, for sure, a different problem then, sounds like there is indeed a fault that will best checked by a pro then.

I know most laptops will do this sort of thing by default in which case - the advice is good, but no , not in this case.

Good luck man - sounds well annoying.

[mattp]

I did exactly this and it cured the noise from my Sony Vaio.

Originally Posted by AVX23

there's a really easy way to sort this out which is tried, tested and cheap.

Take a 4 way or even just an extension lead, whatever - you only need one socket.

Remove the earth connection and seal it up.

Plug your laptop into that.

No more mains hum.

It's the earth that causes it.

You can also buy boxes as per above which will 'clean' the power source.

I normally run said extention into a surge protect device in case I fry my laptop, I've never had a problem with this yet and I've used in clubs, fields, warehouses and the worst place of all......my hovel.

are you saying one day this was fine, next it was not ? could be maybe you've never noticed it before perhaps ?

[emef]

yep i just did it too with a dell inspiron 8200, and it sounds as clean as a whistle now.

[mattp]

I would like point out that I did take someone elses advice and tape up the other sockets on the 4-way with Red tape so as not to plug anything else in it.

[stinkfinger]

another thing to point out is: as long as you have your laptop either plugged into a firewire interface or even just going from the headphone out into a mixer, it will be grounded anyway. because the interface and the mixer are grounded. that what causes the buzz in the first place. having the laptop grounded AND the mixer/ interface grounded is what causes the loop.

[amble]

oh hello again thread. been a while.

the problem is gone now, allthough i'm still not all sure what it was, weirdest thing ever..

wasn't the power supply as i suspected, wasn't anything about ground loops either. i had Dell change the power supply, graphic card, display, internal soundcard and finally the mainboard (each seperately) - nothing helped. thought i was going mental and gave it up. some time later by coincidence i discovered i hadn't installed Direct X and put that on again. turned the machine on few days later and the feedback was gone. hmm?

as i said still not sure if that was it but i'm glad it's gone now. i won't cry about the fact i got practically my whole machine replaced for the price of a Direct X installation too.

anyways thanks for all your opinions, big up vestpocket technican crew!

[love_tempo]

Actually, now that you mention it a colleague at work has the same problem with his graphics drivers on win xp 64.

My work computer has started tocking intermittently like a clock and my bosses started smelling like fireworks yesterday and emitting blue sparks.