Tablejockey is 100% correct. I own a tube phono preamp, and the tubes in similar phono pres are obviously preamp tubes, hence, phono preamp. Preamp tubes don’t really need to warm up too much at all. It’s power tubes in poweramps that need to warm up a bit before you reach optimal sound quality. Preamp tubes more or less do the job of shaping the sound and adding gain, where power amp tubes are the ones that really do the work.
Thats a very abridged version, but I’m sure you get the point. There’s much more to it, but in your situation, Tablejockey explained what to do.