Here is a simple recommendation. If you are investing in a tube amplifier, your investment dollar will be best served if you get a speaker that is at least 8 ohms, particularly in the bass region. 16 ohms is even better. All tube amps, regardless of technology (push-pull, SE triode, OTL, etc.) will show improved performance if used on higher impedance loads. Output transformers will have wider bandwidth (particularly in the bass region) and less hysterisis loss (which can be up to 20% in some designs).
As a result, all other things being equal, a tube amp will measure and sound better on an 8 ohm speaker as opposed to 4, and better yet on 16 ohms (providing a tap is available) as opposed to 8.
FWIW.
As a result, all other things being equal, a tube amp will measure and sound better on an 8 ohm speaker as opposed to 4, and better yet on 16 ohms (providing a tap is available) as opposed to 8.
FWIW.