Im no expert, but mixers with a valve in the signal flow seem an interesting concept in regards to using CDJs . Having an affordable rotary with a value element, making the sound for all formats feel “warm” would be good. Seems like that Mastersounds valve rotary is the best bet.
Im sure back in the day there was a valve box you could add in between a source line out / then line into the mixer, or master out / into speakers . RED sounds maybe? Time for Google……