Great for the TubeMeister18
I replaced the stock tubes in my TubeMeister 18 with a pair of these Mullard EL84 (and some EH 12AX7 for the preamp) and the already good-sounding TM18 now sounds fantastic. Rich but smooth texture. Easy to get saxophone-like sounds from the lower registers of the guitar, which is a sound I've been seeking for years. I use my TM18 as a signal processor only and can't vouch for these performing as well when driving a speaker - but they probably do.