Ringing amplifier

I was near my amplifier the other day with the system off and shouted for some reason and was surprised to hear a ringing noise for a few seconds after the shout. The sound was coming from the heatsinks because it's easily stopped by applying light pressure to the heatsinks with a hand or arm. The amplifier is a Classe CA-200, the later model with the big heatsinks on the sides.

The ringing noise was pretty quiet. If the system was on I doubt I would hear anything when close to the amplifier, and surely not from the listening position. If excited by the louspeakers, I doubt the noise coming off of the heatsinks will do anything to degrade the sound in the room. It doesn't seem like a big deal to me.

Is there something else going on when components ring? Does the ringing somehow manifest itself in the audio signal and get amplified by the amp? I'm wondering why ringing is believed to be so bad if it can't be heard from the listening position.