Tube Replacement Advice

For EL84, the best but near impossible to find is Lorenz. The second best(s) - Valvo disk getter then Telefunken.

William you are correct. I was looking at a zip lock bag of replacement tubes and the 12 AT and 12 AU were together, remnants of my days with Atma-Sphere.

The 7316 is a replacement for the 12 AU and works wonderfully in the older driver circuit of the MA 2.

I believe the 7316 is a 12au7 sub NOT a 12at7. The Sylvania Gold Brand 6201 is a great 12at7

For the EL84, this tube is also 6BQ6 and 7320. Best ever is the Telefunken if you can find them. Then a three way tie with Siemens, Dutch Amperex and Mullard.

For USA 6BQ6, late 1950’s RCA black plates are excellent and likely one third the price of Telefunken's.

The 6414, I have no personal experience with these but have heard that the old Raytheon is a good tube, much better than currently manufactured stocks.

The 12AT-7 is easy, Telefunken. If you cannot find Telefunken, the Amperex 7316 is excellent with great dynamics and (usually) very quiet. Good luck with your tube rolling.

Try asking the Manley folks. I understand they will take the time to talk to you.