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?
Don is correct!!
This is an ancient problem- and it does not matter if your preamp is tube or solid state! You **always** **always** turn the preamp on first and allow it to settle before turning on the amp, if the amp is solid state. Some of the biggest sounds I've heard from breaking this rule have come from solid state preamps!
It was a bad move on the part of the manufacturer to place the power switch on the back. You'll just have to deal with it.