Micro Cube Sound

So my Micro Cube has this really odd problem. Happened to someone else I know also. Sometimes theres no difference between when the volume is turned up half-way, then when it's all the way. The sound kind of zones in and out, and sometimes it's alot quieter than it should be. Has this happened to any of you? If so, what did you do?

wow that doesn't sound too good, my microcube has been pretty good so far. If you've still got warranty use it before its expired! Does it do the same thing say if you have headphones plugged into the jack? ( i mean in the headphones btw :P )