Loud pop/screech when powering on amp

Hello All,

I have an Audio Refinement Multi 5. I just bought her used in pristine condition a couple months ago. I get a loud pop when I turn it on. But the last couple of days there's almost like a weird screeching sound right after the pop . Everything sounds. fine when I play music/movies, but I'm a little concerned if this is a bad sign. I'm also a little concerned if this is harming my speaks. I have had other amps that pop and I know this is normal. I always turn her on last and turn her off first and volume is always low when powering on and off. I only use the power button in the front when done for the night. I have not turned the main power button off since connecting her. I have a Shunyata power cable plugged directly into the wall on the amp. I have an Audioquest Powerquest 303, should I maybe try plugging the amp into that, would that help? I also did turn off the main power switch on the back this morning and will try when I get home to see if this helps when I power her up...

Thanks in advance for any advice...

Best Regards...