Weird buzzing noise when recording guitar with Mobilepre MK2

[hyyz17200]

Hello here,i got mobilepre mk2 in october last year.
The noise is so strange that it only happen when recording guitar.If i record vocal, everything is fine.

The noise not always buzzing,only when i play the string, if the guitar sound is loud,almost none.But wating for the guitar turn to silent,in this progress,the noise shows up!
Maybe my words are difficult to understand, so you can listen the sample audio below:
(for hearing clearly i maxmize the volume)
http://e.nono.qisns.com/1.mp3

I have the cheap e-guitar,first i think maybe its my e-guitar problem.But my friends use his great guitar to record on my mobilepre , things the same.
http://e.nono.qisns.com/2.mp3

Maybe the cable? But when connecting to ampfilter, no noise like this can be found.

Whats more , these days, I use my dymanic mic to record acoustic guitar,the noise shows too!
http://e.nono.qisns.com/3.mp3
So i turn to crazy.

I think about the EMI. So I tried unplug my laptops power,change to desktop pc,and even change my recording place.Nothing works...

Whats the reason? Anyone can tell me ? Is something wrong with my mobilepre ? Should I send to repair?
Please help,thanks first!

[Emcha_audio]

Looks like you have a ground problem.

[hyyz17200]

Originally Posted by Emcha_audio

Looks like you have a ground problem.

Thanks for reply!

But I unpluged my power adapter from laptop. If its ground problem,it will be solved. Also I connected to desktop,and i'm sure the ground connection of this pc is good.I use multimeter to test power socket , everything fine.

Today I take mobilepre to my friend's home,use his pc,his cable,his guitar.Things the same. He has a Line 6 POD HD300,and recording is fine!

What can I do then?

[Emcha_audio]

A ground problem can come from any piece of your equipment, not just the pc or laptop. If for any of the equipment you are using has it's ground broken you could be getting the problem from there.

[hyyz17200]

Originally Posted by Emcha_audio

A ground problem can come from any piece of your equipment, not just the pc or laptop.

Every equipment has changed except mobilepre.
The point is, why the same equipments(Guitar,cable,pc),with mobilepre,there is noise,but with his Line 6 POD not?

So can you gimme some advice for solving? I'm almost sure its wrong with this mobilepre...