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sted
16-08-2009, 09:42 AM
Ok having huge problem with my computer, I built it about 6months ago and has worked with no problems until this week when I gave it to a shop to change it over to a rack mounted case. Picked it back up on Friday for my gig on yesterday got home tested it and was getting huge interference through the speakers. Rang and spoke spinmasterdisco and he said I needed a ground loop isolator and maybe try a feral ring. so went maplin and bought to rings one for each end of the jack to phono and a ground loop isolator tested and it seems ok. Got to the gig and it was worse than it was when I picked it up so ended up using my laptop.

Anyone any suggestions really stuck at what to do.

Rowleys
16-08-2009, 10:01 AM
i have this problem and tryed then groundlopps ever worked but when i conected an external monitor the noise stopped

so now i put a ground link to the vga bolt and all stopps

discomobiledj
16-08-2009, 10:04 AM
It is a simple grounding problem you are having. Trying to isolate where the loop is broken is the fun part!

sted
16-08-2009, 10:05 AM
any suggestions? will it be in the case itself?

discomobiledj
16-08-2009, 10:14 AM
To be honest it could be absolutely anywhere, normally it's the leads into/out from the mixer, but seeing as your using a rack mounted case, it could be that.

It really is a case of trial and error with it. Also from venue to venue.

I have one place where I have this exact problem, the ground loop isolator sorts it out anyway, but it doesn't happen anywhere else, you may find that as well.

Rowleys
16-08-2009, 10:15 AM
Sound like there is a floating earth on there some where ..

get it to your PAT tester and see if the case is earthed

can you take a pic of it as I'm not 100% sure what it is

is it like a big PC in a rack case EG

full size motherboard full size HDD and a big power pack built in ??

Just try ..

getting a piece of wire put it on the ground on the back of the mixer and put it on the PC case make sure there is no paint stopped the metal and wire connecting

DiscoPromotions
16-08-2009, 10:22 AM
What type of soundcard are you using?

Internal, off the board or external?

sted
16-08-2009, 10:33 AM
http://i302.photobucket.com/albums/nn100/sted123/fd60_1.jpg

http://i302.photobucket.com/albums/nn100/sted123/fe2b_1.jpg

this is the case and i am using an internal sound card.

i dont think its the venue (as it happens at my house too) although how would this make a difference?

DiscoPromotions
16-08-2009, 11:07 AM
I think I know what the problem is here. As you got 2 external fans on the case there is no earth for them.

If I'm correct the noise you are hearing is constant buzzing sound.

This is being caused by the fans interfering with the soundcard (this is common for internal soundcards).

What you could try to rule this out is power up the unit without the external fans and see what you hear then.

sted
16-08-2009, 11:50 PM
you were right now how do i fix it?

DiscoPromotions
17-08-2009, 12:12 AM
you were right now how do i fix it?

No real cost effective solution resolving it as the fans do not have earthing on them.

Easiest solution is keep the fans disconnected permanently, which is not really best solution as computer boards like to be kept cool as much as possible.

Simple solution is to buy a quality external sound card, but do be-careful as some external like Edirol sound card do not improve the situation. Numark DJ IO is quality card as reduced a problem I had with a laptop with the same problem of fan interfering.

Also, check the earthing on your machine to ensure it is probably grounded.

sted
17-08-2009, 07:59 AM
thanks for your help