strange sound

I am getting a strange sound from my speakers when I power down my system. I shut everything down (amp, preamp and source) and about 15-20 seconds after that, a sound starts high in pitch and slowly drops in pitch (kind of like a bomb falling from the sky in cartoons) until it stops about 15-20 seconds later. It happens every time I power down. I have no other strange sounds or problems at any time during power up or during listening.

Does anyone know what could be causing this?

Thanks for any insight.

Showing 3 responses by snicka

I tried it manually and it does the same thing.

It is not a tube amp.

Thanks for the input.
Thanks again for your help.

The sound does bother me but not enough to spend a lot of money to fix it.

I do follow the same power up / power down procedure as you described. Actually my Panamax surge suppressor does it automatically for me. It has timed outlets for amps and such.

Thanks for your response.

Do I have to have the capacitors replaced to get rid of the problem?

Will leaving it alone cause any damage to the amp or my speakers?

Thanks again.