Tube amps known to have a low damping factor?

Which tubes amps are known to have a characteristically low damping factor, 20 or less? Which are known to have a characteristically high damping factor?
Compared to ss amps most tube amps have lower damping factors. Wolcott tube amps appear to be capable of a rather high damping factor for a tube amplifier.
Some amps with a high damping factor have little or no global feedback.
In tube amps the loop negative feedback is a big factor in the resulting damping factor. For example an OTL can be built with a damping factor of 50:1 if you have enough feedback. IMO such a large amount of feedback does nothing to improve the resulting sound, and also it should be considered that no speaker made needs more than 20:1, and many of them like a lot less.

An example of the latter are open baffle designs- in order to get them to play bass the amp might have a damping factor of 0.5:1 or less and yes, that's not a typo. IOW, a *lot* depends on the speaker and the designer's intent!
Are there any tube amps with DF higher than 20? You don't see that much, I don't think.
ralph noted...a *lot* depends on the speaker and the designer's intent!

AMEN. Look backwards from any driver after a crossover and let me know exactly how high (or low) DF can be a meaningful figure of merit.