Buzzing noise when playing into an amp

[soundground]

I have had a problem I am unable to remedy for many months now. I am performer in Europe, and I do real time sample manipulation for a band. I am using a Tascam US-122 as my external soundcard and controller on a Dell Inspiron. The soundcard is inputed to a small 4 channel mixer (but the problem occurs regardless of whether or not I go into the mixer)

The problemis this. When I play concerts at larger venues, the soundguy plugs into my tascam. The sound is clear and perfect. However when playing at smaller shows, I often need to plug into a smaller guitar amp. When I plug into a smaller amplifier, there is a terrible noise emitted from my system. Making things stranger, if I unplug the power from my computer the sound immediately vanishes. I am thinking that this is a type of a ground loop problem. I am thinking that perhaps my computer isn't grounded well enough because I have had to put an adapter on my american plug to accomodate the european size. However the adapter does have a grounding metal plug which I plug my american plug into.

The strange thing is that if I plug my system into my home entertainment system there is no noise, and also as I have stated earlier, when I play larger venues. The noise only comes when plugging into a smaller guitar amp. And yes, I have an amp that has a line in, which generally would accomodate a cd player, I am not plugging into the guitar input. and either way, the noise goes away, as soon as I unplug my computer.

I have also experimented with trying to move the power cord, and sound cords as far away from each other as far as possible. This has no effect on the noise. The noise is steady, and does not change when I turn up the volume on my external sound card. Anyone have any ideas how to get rid of this noise?

thanks in advance

 

[WorldIndustries]

Is there a monitor attached to that computer?

 

[molsen]

certain equipment combinations will cause that to happen... a good ground loop isolator should be a part of any live setup.

 

[RicoDirenzo]

It's the guitar amp. Preamps for those uints are not designed for direct audio input from a preamp source loke a computer because there is to much pre signal gain from your puter sound card. That's what mixers are for. You need to invest in a rack mount mixer and patch into the system. Been there and done that and it doesn't work. Guitar amps are for guitars. Wrong input device!!!!

 

[EricB]

you are converting voltage to something that already has a switching power supply

try running a ground wire from the computer case screw to the guitar amp. you can try a ground loop isolater or break the grounding plug of your computer or your guitar amp

or use these to troubleshoot the loop instead of breaking the ground plug. you won't have that extra groud protection, but that isn't that big of a deal if you have everything wired properly

 

[RicoDirenzo]

You want to sound like a professional? Pop for the Mixer.

 

[molsen]

yea mixers are the way to go... you can get some fairly inexpensive 6-track mixers from behringer...the euroracks...great quality for around a hundred bucks, sometimes less. check out www.musiciansfriend.com