Just got one of these to replace a broken Tosh XS32. The Tosh was noisy in that the fan made an audible "air rushing" noise, which I could live with. But the Pioneer makes a kind of vibrating noise. Not at first - when I first turn it on I can hear the disk spin up, then the rattle as the heads load. Then 3-4 seconds later there's an ascending rrrrrrrrr noise, like a loose bearing. When I turn it off again the noise rises in pitch briefly before stopping as the machine shuts down. Is this typical or do I have a bad 'un?