Out of tune? YEAH - that's the joy of analog for you!
On stage, Rick Wakeman could/can regularly be seen tuning his MiniMoog between songs.
Man, I'm so old I can remember the first TransAtlantic TV broadcast via the Telstar satellite. There was nothing like turning on the tiny black-and-white 'TV set' and having to wait a few minutes for the valves to warm up before there was a stable picture!
In addition to schooling you in THE ZEN ART OF PATIENCE, another advantage of the use of vacuum valves was that you could keep your toasted crumpets warm on it (before buttering them, of course). ;-)
If you can't stand waiting patiently in the lotus position for your French Monster to warm up and play in tune, you can always trade it for a [puke] DIGITAL SYNTH. ;-)