Power Supply Cord NOISE???

  • Thread starter Thread starter jonnybrenner
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J

jonnybrenner

New member
Hey everyone. I love this site. (I am new at posting) I have just started up my own home studio and have a basic Sonar 7 set-up with a nice HP dual core laptop with firewire interface. Yada Yada...

Now onto my problem... When the laptop is plugged in there is this aweful static noise that comes through the recording. I hear it from the firewire interface headphones and it comes through during mixdown too. When I unplug and run on the battery it goes away. I tried plugging into different outlets in different breakers and through a power conditioner, but no help at all. I haven't tried a power filter to plug into, but I wanted to make sure that it would solve my problem.

Any Help?

Thanks,
jonny
 
Are you using an IBM laptop (as opposed to a Mac)? Because this happens all the time live, not sure about recording as I've never used one to record on.
 
It is not a MAC. It is a HP Laptop with dual 2GHZ each processors. It has 2 Gigs of RAM.
 
Could be an earth loop. Is something else apart from the laptop's power unit also plugged into the mains that's connected to your setup?

Also, keep the power supply box well away from your audio inputs, preamps etc.

T
 
Here is what I have tried...

I had another laptop that I used prior to this one and the sound was there too. However, when I mixed it down, it wasn't an issue. Now, it bothers me because it comes through the mixdown as well.

I plugged the mixer, firewire solo interface, and laptop into my power conditioner and that didn't fix it. I have moved the wires and they aren't touching anything. I tried plugging into different outlets and no solution other than unplugging it and running on battery.

Is there some sort of noise from the power adapter supply? Is there a way to filter this?
 
Happens a lot with laptop power supplies. Sometimes it can be cured by using a grounded (3-prong) adapter...sometimes batteries are the only way to go.
 
I would try to obtain another power supply - borrow it or see if you could use one at the store you bought the machine at. This way you can determine if your laptop's supply is not working properly.

The type of power supply used for a laptop is very sensitive to changes in the way it's component parts are manufactured. For example, the manufacturer of a little diode being used in a laptop power supply may have changed the production process for that series of diode. This results in their diodes operating with slightly different parameters. The power supply for the laptop has been engineered to use the specs of the original diode so now there is a discrepancy in the performance of the power supply. As far as the company producing the power supply is concerned they are using the same part. It could take awhile for them to notice the difference.

I've seen this sort of thing happen working for various electronics companies.

Anyway, try it out. Try to get your hands on another supply and see if the problem persists.
 
If you're using an external CRT monitor with that laptop, you might be getting RFI bleeding into your power line or your audio monitor lines from the CRT. The easiest test would be to turn the CRT off and see if the noise goes away. If so, then re route your audio monitor cables and your power cable to the other side of the monitor or away from it to get rid of the RFI.

G.
 
this has been long established problem with laptops... usually batteries are the only hope... but you might try a ferrite ring... you simply loop the power cord through it say 1/2 doz times... it has worked for me with a small tascam mixer i used to submix my keys at one time...
 
:confused:

Wow. It really seems like I am screwed? Who wants to unplug and run on batteries to record??? I hope that this isn't my only solution. I really appreciate your thoughts though. Thanks gang. I don't have an external monitor hooked up, so that isn't the problem for me. What is a Ferrite Ring?

Thanks for info! :)
 
dementedchord said:
this has been long established problem with laptops... usually batteries are the only hope... but you might try a ferrite ring... you simply loop the power cord through it say 1/2 doz times... it has worked for me with a small tascam mixer i used to submix my keys at one time...
Click to expand...

This is a good suggestion. Radio Shack should carry items like this for $5 or so. If you have no luck with them I can point you to other sources.

Also, see if your laptop is still under warrantee. Then use that to obtian a new power unit...
 
Somnium7 said:
Also, see if your laptop is still under warrantee. Then use that to obtian a new power unit...
Click to expand...

Nobody is going to warranty that, cause it's not broken, unless you happen to run across a very sympathetic service person. Even then, don't count on finding anything quiet. Laptop power supplies just suck for noise, and really until the problem starts to affect the mainstream buyer computer companies won't care.
 
boingoman said:
Happens a lot with laptop power supplies. Sometimes it can be cured by using a grounded (3-prong) adapter...sometimes batteries are the only way to go.
Click to expand...

Good advice, And the adaptor is likely to do the trick.
 
Solution found!!!! Thank you all

Ok Ok... I have taken all the feedback in and found that the solution is this simple....

I used a "Three prong grounded to 2 non-grounded " Adapter. Basically the quick fix for taking a grounded plug into just 2 to fit extension chords or an old outlet that only has 2.

It worked. It stopped the ground static noise.

I hope that this info helps the next person dealing with this problem.
Thanks gang!
 
Thanks

Sat here in my poky little studio marvelling at the depth of know-how on here. You've certainly given me some food for thought too.
Maybe now I can stop doing the power cord shuffle every hour, so thanks from me as well!

:)
 
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