DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: Joep on March 24, 2004, 06:31:06 PM

Title: OT: Noise from computer
Post by: Joep on March 24, 2004, 06:31:06 PM
Hi All,

I have both my computer and my GT-2 clone connected to a mixer. I noticed a lot of noise especially on the high gain settings of the GT-2. Recently I realized the noise doesn't come from the GT-2/Guitar but from the computer. As soon as I connect the computer to the mixer there is a big increase in the noise level. I have an TFT screen, so the noise isn't coming from the screen, turning it off doesn't make a difference.

Did anybody else noticed such a thing? Or does someone has a good idea to get rid of the noise?

Thanks,

Joep
Title: OT: Noise from computer
Post by: Arno van der Heijden on March 24, 2004, 07:05:52 PM
It's probably the fan...
Title: OT: Noise from computer
Post by: Hal on March 24, 2004, 07:39:47 PM
shielding the guitar will probably help you TONS.


check out www.guitarnuts.com for some info....
Title: OT: Noise from computer
Post by: Paul Perry (Frostwave) on March 24, 2004, 07:55:57 PM
It could be the switch mode power supply in the PC.
I suppose it would be possibe (though I have never heard of it being done) to run the PSU externally, some distance away, with mains type fileers on the power leads to the computer. (watch current ratings).
Title: OT: Noise from computer
Post by: Paul Marossy on March 24, 2004, 09:40:25 PM
I think I have to agree that it's the fan. Try using a wah close to your CPU, and you'll pick up noise from the fan with no problem... and your pickups will, too. Shielding your guitar would probably help quite a bit.
Title: OT: Noise from computer
Post by: Joep on March 25, 2004, 03:42:23 AM
Hi All,

Thanks for you answers, it made me thinking.

The noise isn't induced into the pickups or something, I tried walking away with the guitar and holding it very close to the computer. No difference. Actually, it I disconnect the computer from the mixer he noise was gone, the only thing I had to connect to the computer was ground to already have the noise. So that led me to the conclusion that Paul Perry was right.

I noticed I didn't use a grounded mains connection. So as an experiment I connected the ground from the mixed to a piece of clear metal from the central heating system (grounded), and the noise was completely GONE!!

I guess I really need an grounded mains connection.

Thanks again!

Joep
Title: OT: Noise from computer
Post by: Paul Marossy on March 25, 2004, 10:11:51 AM
Cool. Sometimes grounding the power supply on something that doesn't have one fixes problems like yours. I have had some similar experiences.
Title: OT: Noise from computer
Post by: Joep on March 25, 2004, 02:39:35 PM
OK, it took some effort but I made a grounded (wall) mains supply now. I had to add an extra wire because it wasn't there. Connected everything back again......

Noise is gone!