The Perreaux phono preamp is a op-amp based unit, not necessarily bad, but it is what it is.
Turn the unit on and leave it on, play it a bunch, and then compare its sound over several days...
Back in the '90s and early 2000s, I read many manufacturers of high end solid state gear advising at least a 48 hour warm-up before doing any critical listening...saw it from brands like Theta...
The solid state gear in my system always, always takes a couple of days to return to what it was before shutting them down and letting them "cool off", my ModWright takes a week, I have a friend with Rowland 735s that I listen to and set up for him and they take a couple of weeks to come back up to really sounding good if you should turn them off and let them cool (I'm at his home 4 days a week working for him in a far removed part of the house, so it's not my ears getting accustomed to the gear either)...his Pass XA200s take a day (and what a heat source they are!), his tubed ARC Reference 6SE preamp and 160M amplifiers sound better after about 6 hours of on time...
One of my best friends, in fact he was the one instrumental in getting me into higher end audio back in 1973, has a Conrad Johnson Premier 11a that has been upgraded and maintained by CJ...he never believed me about leaving the amp on over night and then listening to it the next day....well, just in the past year he did that and had to call me up and tell me how surprised he was that the sound quality in his system was improved to a large degree...he wouldn't have believed me if he hadn't tried it...good quality gear, Spendor speakers, Audience upper tier cabling, etc...
I never turn off low current solid state devices, like DACs, CD players, preamps, streamers, never...in fact my Audible Illusions tubed preamp has been on pretty much 24/7 since buying it new in September 1998...I do have a case of 200 Yugoslavian 6DJ8s and use Pearl Tube Coolers on the tubes so I don't worry about tube longevity.
I've been playing with this stuff for nearly sixty years and these are just some of my observations, but I'm learning new stuff all the time...