I had the same problem with a 25 year old Bryston 3B and was told Some amplifiers have capacitors that discharge when the power is shut down to them as well. Most of the time I just left the amp and preamp on, which I believe sounded better because it was always warmed up readt to go.
when shutting down my system the speakers squak
i have jbl three way loud speakers, they are tri amped. im using sae power amps from the late 70s and early 80s. no matter how i shut the system down, preamp off first and power amps second or the other way around, i get ungodly squaking sounds from my speakers. my power amps are plugged into a adcom line enhancer. no one ive talked to knows why this occurs and how to remedy this problem, do you?