A lot depends on the ESL! Sound Labs and older Quads like the ESL57 and ESL63 are good matches with tubes.
Martin-Logans are designed (meaning they have a lower impedance but otherwise have an impedance curve typical of ESLs) to work with solid state; all you need to get a tube amp to run them might be a set of ZEROs (www.zeroimpedance.com). We've got customers that have been running our amps (which are zero-feedback OTLs) in this manner quite successfully with MLs for many years.
Martin-Logans are designed (meaning they have a lower impedance but otherwise have an impedance curve typical of ESLs) to work with solid state; all you need to get a tube amp to run them might be a set of ZEROs (www.zeroimpedance.com). We've got customers that have been running our amps (which are zero-feedback OTLs) in this manner quite successfully with MLs for many years.