Tube info

I have some Conn 12AU7s that sound terrific in my phono preamp. The organ manufacturers used lots of tube manufacturers, but generally tested their tubes very stringently so they're usually a good bet.

Thanks guys. @ Lowrider57, I will be building VTA M-125 mono blocks and that’s what they’ll be used in. @bbroussard, I’m not sure on a budget. I’m not a big $ spender on tubes though. I’m thinking maybe $30/40 each. I would need (4) and that’s why I’m trying to stay economical. 

I like 12AU7 CiFTE and RT. They sound « real » in my system.

What sound are you looking for and position really matters driver vs input etc. Anyway you have a nice long list to choose from at reasonable prices. My favorites are Amperex yes esp 7316 overall detail and excellent tonal balance very quiet and for a strong clean signal use a 5814 mostly RCA. these are also consensus picks good luck and roll what you don’t like. Want a mellower richer tone go for a Mullard or Brimar!

The M125 monoblocks...
http://www.tubes4hifi.com/bob.htm

There are indeed only 2 driver tubes on each monoblock. If I’ve read this correctly, the driver stage generates higher than typical voltage, so there isn’t a separate gain stage.
The sonic effect of the driver tubes will be significant.