Hi all, I've recently noticed that when I switch to or from standby, a little blue spark can be seen thorugh the tiny space between the rocker switch itself and the plastic surround mounted to the face-plate. It can also be heard through the speakers. When coming off standby to play, a small 'fizzle' is heard for a few seconds and fades away. The same sound has been there the entire time I've owned this amp (1 1/2 yrs) so the spark has probably been there the whole time to, but I've only become aware of it as of late. Would there be a problem?? Is the spark normal?? Please any info is greatly appreciated.