What model laptop and what model power supply are you using?
What audio interface?

manbag

Where you planning on the DI box in the signal path? Hold off on that yet.

quote:

Originally posted by DJ 00 Tommy Iv heard of cutting the pin or buying some kind of adaptor without it but then there is the worry of having a power surge or some kind of power interfearance that will fry my laptop.

I doubt very much these adaptors would even be legal here.

Sounds to me that the power converter is of a cheap nature and the build not high spec. Once the ac is changed to dc, there can be a riple in the flat Voltage . Sounds like it needs a better DC smoothing capacitor (after the bridge rectifier in the step down transformer). See if that helps?

Iv had my brother draw diagrams and explain about the ac to dc process and how there is most likely that ripple in the dc with the little arcs and such. And that the noise is most liekly that.

I was thinking of using a DI box between my mixer and my amp. If the problem is from the conversion then the noise is dc. Lots of DI boxes have isolation transformers meaning no dc can pass. Exactly what a ground loop isolator is.

Also: If i could i would just go and buy a better power supply but i cannot find a third party one for the Acer Travelmate 4060 series.
If i do find one it will probably cost atleast $100 where as the di box or grond loop isolator will cost much less.

I'm no electronic tech, so forgive my ignorance, after the DC cmoothing capacitor is the regulator - I think that is where the fault lies (could be wrong).
Not sure that plunking in the DI will alter anything, as if it is the power supply, it is likely to be affecting the audio signal itself, and would therefore pass through the DI. I guess the only way to find out is take try it out, just make sure you can return it if it doesn't help.

quote:

Originally posted by DJ 00 Tommy What model laptop and what model power supply are you using? What audio interface?

acer travelmate 250
standard adaptor
m-audio quattro

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thesuperglo - Flaming Popsicle [June 2007 Promo](full-on/dark/goa)

Try this: Plug in the power supply, boot up your laptop, make sure you hear that noise. Then remove the battery from the laptop. See if the noise is still there.

if it is:

Try using 3 pin to 2 pin power coupler. Like the others said, it removes the ground pin which somehow might be causing the ground loop.

if it still there:

Try coiling the power supply's wire around a ferrite choke closest to the laptop. Try also coiling it closer to the power supply. See whichever sounds better. Go to radioshack and ask for this: http://www.radioshack.com/product/i...rentPage=search
Make sure to make 5-6 coil turns, do not just snap this on the wire, like some RS clerks might tell ya. Do not listen to them and buy a $200 power supply for the laptop either. Most of them know shit about electronics.

the reason why superglo never had this problem is because he/she uses an External sound card connected thru usb or firewire, therefor not subjected to any electrical noises inside the laptop.

These adapters being spoken of are likely to be banned in Australia. I doubt the govt would allow a product which enables you to disconnect the ground from electrical equipment.
To prvent a ground loop, don't provide more than one path to ground, i.e. use a power board, and run the amp and laptop off the same wall socket.

Iv got an exnternal soundcard. The interfearance just runs through anything connecting the two. Iv tried many combinations when it comes to power outlets/boards.
That ferret choke thing is interesting but im doubtfull about whether it will work.
I think i will just take the laptop down to an electronic store and see if i can just test out a bunch of isolation transformers.

try pulling the battery out of your laptop while booted up and connected to that power supply. The charging controller might be making bunch of noise.

Try putting chokes onto the USB cable next to the sound card. Try connecting that sound card to the desktop. Isolating transformers will ruin the sound quality.

It also depends what kind of noise you are experiencing. Record it and post it here, i should be able to tell whats causing it.