Need help, Vox Mini 3 annoying noise

[Stoyo]

Hello, about two weeks ago i bought a Vox Mini 3 and i was very satisfied by the sound and how clear it sounded. The problem begun when i plugged my mp3 in the Aux In to play along with backing tracks. Since then a weird "Shhhh" is present and i can hear the flanger going "ouing ouing ... " within that noise. I play mostly in quiet environment and it is really annoying.

The amp was sent two times to the technician, the 1st was returned as "normal" meaning that the noise is ok to be there because another brand new amp had the same noise. I sent it a 2nd time and went there to see if it is really checked - i am SURE that at the beginning it was totally silent - and i just heard that both amps, new and mine, had the same noise. On another forum i was told that the Aux In has a metal contact that creates grounding to stop the noise when Aux In is not in use. That contact must have gone off its place and thats what creates the noise. I would like to hear your thoughts please. If i have to send it a 3rd time for service i better be sure.

Excuse my english!

[Jazz P Bass]

Plug an accessory cord into the Aux jack & ground the tip to the ring.
If the annoyance goes away then, yes, it is the Aux jack.

[Stoyo]

Plug an accessory cord into the Aux jack & ground the tip to the ring.
If the annoyance goes away then, yes, it is the Aux jack.

Smart advice, simple and easy, thanks a lot!

[Stoyo]

It didn't work, the noise still remains... What i noticed is that when i plug earphones i hear the Flanger and the Room effect noise through earphones and from the speaker there is a constant noise like when i have all effects set to "0". That shouldn't happen because when the earphones are plugged the speaker goes off, thats what the manual says. I have recorded the noise and will try to contact Vox to help me with the problem. I still believe i am not crazy and the noise was not there at the beginning