12AX7 for this. There is another wire in the middle though I imagine the 6.3 will run as they all have the same pin out. I actually got some nice 6N2Js and they are comparable to some matched up old RCA Black Plates. The RCAs have a lot of use on them, but I noticed no improvement over the 6N2s (Chinese and probably Shaguang like the EL-34s are which arrived in the sockets, so no boxes) I plan on rolling 12AY7s, 5751,etc and I think I will pop for some JJ E34Ls or what ever they are. Open to suggestions on the EL 34s. The Mullards were too tired to stand up to the Shaguangs. Not even close.
The 5Z4s aren't even close to good. Good for burn in and then for testing, but with the SEPs a 5V4G will give you want. 5U4Gs might too, but they power on hard. Tried a Mullard 5AR4 and the old 5V4G sounded better in this amp.
I just bought a no name amp, the brass plate says TUBE, so I think I will get to name it myself.
Great Googly Mooglies! Land Shark.....No!!! I have it! "Bassomatic"
Thatch