I'll second the Seimens for EL-34's. As for 12au7's did alot of tube rolling with these and found Amperex 7316's to be the best. Has the speed and clarity of Telefunkens but not so thin sounding. Full midrange of Mullards but clearer and more detailed. By all means there are tons I haven't tried nor have I gone into the rare and expensive but for around $100 a pair (my limit) they are fantastic and worth the extra $.
