Some amplifiers have capacitors that discharge when the power is shut down to them. Your SAE's might be one of these-I had a PS Audio amp that did that, it made an awful cracking sound when I shut it down, so I left it on all the time.
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?