#1
So i really have no idea where to put this thread, but i guess this is the best place.

Recently my band started practicing with a click and backing tracks, since we are getting ready to record our stuff. The chain is like this: Laptop->m-audio fast track pro->mixer->IEM for me and the drummer, and also on PA for the other guys.
It works pretty good. Its not perfect, but seeing as we only need it for practice, its ok. That is, tho, until i plug the power cable into the laptop. I start getting this hum, and its pretty loud. Its pretty much silent when i run it on battery, but if its powered then it just hums like crazy. I tried other power sockets, i tried unpluging everything we dont need, and the thing still hums. Obviously its because of the electricity, since it works normaly anywhere else. Is there anything i can do about it? The building that we practice in has pretty shoddy wiring, especially our practice room, that has a bunch of those wall mounted cable enclosures that you see in cubicle offices. I thought about using a different charger for my laptop, but i dont have any that would fit (why this things are not universal is beyond me), and the battery only holds up for around an hour, and thats not really enough.

So besides getting an expensive power conditioner, what are my options?
Jo┼ża je kul. On ma sirove z dodatki pa hambije.
#2
I use the same setup laptop->m-audio fast track->mixer. I notice that whenever I am close to the laptop screen or if I touch the trackpad, the humming gets very loud. However, plugging into a grounded powerstrip helps. Also, I play far from the laptop now - I use an iPad as a remote.
#3
I get that when I got my guitar plugged into my laptop too, seems mostly noticeable on distortion (especially with the virtual software pedals)
Though they go away as soon as I remove the charger..

I guess you could tone down the distortion level or not charge and play (though not entirely sure how that practice room works/is set up)
#4
I ran into this issue with a PreSonus Audiobox. The issue it turned out was due to grounding. Same result - battery operation resulted in low noise, but plugging in the laptop created electrical hum (more of a whine in the case of the PreSonus/my setup). USB interfaces that are powered off of USB cannot provide proper grounding for themselves and the instruments/equipment attached.

I see that the M-Audio unit you use can be powered off of USB but can also be powered via an adaptor. If the adaptor has three prongs, there's a good chance that using the adaptor will solve your issue. However I suspect it is a 2-pronged adaptor.

For my Audiobox, I wound up experimenting with different power supplies and conditioners, but in the end I found a combination of the right computer, the right room, etc. and it stopped making the noise. I did not find a fix-all, just kept fidgeting until something worked.

Using a grounded preamp in front of the M-Audio may help. Closing grounding loops between your computer power source and all other gear in the room may help.
#5
I use a laptop for midi sequencing live with an internal sound module. The way I solved this problem was to buy a "audio system ground loop isolator" that Radio Shack sells for less than $15. I looked on line and see Best Buy sells one also.
Yes I am guitarded also, nice to meet you.