• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Tube buffer

Nick,

no, i don't think a tube buffer has the sonic footprint typical for tubes. You won't get more warmth out of it.

And no, a tube buffer is not an easy start.
A proper working tube buffer/cathode follwer needs some constant current device as load, else it sounds like junk.
Even then the CF load should be 5-10 times the followers output resistance and as real/resistive as possible.

There is a thread "12AX7 as cathode follower" or the like. Please read it, answers a lot of your questions. And seach for "cathode follower", "tube buffer".