classé makes noise on power off.

I have a Classé CAP-100 integrated amplifier. Within a few seconds of powering it off I hear a strange whistle like sound coming from the right channel followed by the same sound in the left. I have tried adjusting the volume during this time, but it does not have any effect, so whatever is happening is happening "after" that portion of the pre-amp or only in the amp section of the unit. I was using this with a larger set of speakers and do not remember ever hearing the noise, but now on a smaller set of two way B&W speakers I hear it every time. Is this something I should worry about? Is it just capacitors bleeding off or something like that or is it a sign of a developing problem? I am not very familiar with high end equipment (only that I love the sound of this amp) so if this is an ignorant question I apologize ahead of time.

Thanks,

-Lewis