Amperex double-D-getter, late 50's. Better than the Mullard "O" getter xf2 EL34s. I've not heard the "fatbase" xf1 or metal base Mullards but Amperex are the best I've heard. The Amperex are more dynamic and less vieled; two areas of weakness for EL34s. This was in my (then) VAC triode amp which I used for three years. I sold the VAC for a Moth SET amp. I found the SET topology and both the 2a3 and 45 output tubes superior to any of the EL34 tubes I've sampled.
Your choice of EL34's
I would like to hear from some EL34 owners who have a favorite output tube. Your input will give me food for thought and possibly concur with my findings on some of the tubes I have heard. BTW does the Ei fatboy really put out more pwr as I have heard advistised? My thanks to all.