Question regarding pre-amp and amp

Hello everyone,
I recently bought Don Sachs pre-amp and have a solid state amp. While switching off the preamp it gives a huge sound if the amp is on. I checked with Don and as per him I should switch off the amp before I switch of preamp and switch on the preamp before switching on the amp. The solid state amp has a switch at the back and I don’t think it’s made to switch on and off on a regular basis. How is this normally managed? I am sure tube preamp will need to be switched off and few of you might have this issue.

Appreciate your inputs. Thank you!