Which EL34 is your favorite and why?

I’m sure there are several who have tried more than me - but I really like the Amerex/Holland brown-base EL34, xf4 and xf5 codes (basically interchangeable). I prefer them to the Mullard blackburn EL34 (xf2, xf3, xf4) for being more neutral and resolving. The Mullards are great, but just a bit too warm & dark sounding for me. I prefer them to current-production Russians for being more holographic, smoother, and liquid sounding. Though the current Russian Mullards are pretty darn good on the cheap - can't go too wrong on that one. Several years ago I tried Russian Electro Harmonix EL34, EH 6CA7, and Svetlana (New Sensor) and found them to be a bit rough and unrefined up top. The Winged-C EL34 was warm like a Mullard but lacked its 3D depth - so I didn’t stick with those.

I know there are more exotic ones like metal-base Hollands and Mullard xf1, xf2, but I haven’t tried them yet. Very hard to find, very expensive!

I like the modern JJ Electronics E34L. Sounds great and inexpensive

Genalex Gold Lion KT77 reproductions are to me hands down the best sounding current production EL34 type. The tube is a drop in replacement for EL34's in most but not all amps so double check with LM.

I also like the Amerex/Holland brown-base EL34 if you can find them. I also have a quad of British NOS Genelex KT77.