Older Bryston 4B Question

I have a older Bryston 4B that I've got hooked up to a H/K 635 receiver for now as a pre-amp. I like the sound for the most part but I have a weird chirping click at shut down of the amp. The left channel chirps and then the right 5 seconds later. I'm also considering leaving the amp on all the time. That would solve my problem, but I'm still interested in the why the sound occurs. Especially if it is a bad thing. Thanks for any info that you guys have!