Maybe I should’ve said do they impact the lower frequencies more? You own interesting speakers
Ok, I see. If you are jumping between types like from KT88 to KT90 / 120 / 150 then YES, it will usually have more notable impact on bass response - but still contributes a LOT in midrange and HF too. If you are just swapping sub-brands of New Sensor tubes of the same type (e.g. KT88: Gold Lion, Mullard, EH) then the changes are a bit more subtle overall, and not disproportionately noticeable in bass. Swapping NOS versus new production (of the same type) is probably between the 2 - I don’t have experience doing this with KT88, but some with EL34.