Thanks for the responses so far. I'm searching around for the RCA 5751's and Tung Sol 6x4. I think that I may have seen the Raytheon at "tubemonger." I've currently got a GE 6x4WA.
Bill at MorningStar also recommended the TungSol blackplates or Telefunkens for the 12ax7's.
In the meantime, I've got a few 12ax7's that I can roll:
(1) Groove Tubes 12ax7-M
(1) Ei ECC83
(3) Jan Phillps 12ax7WA
(1) Jan GE 5751
various JJ's, Sovteks, EH with good numbers
By the layout of the unit, it appears that the 1 12ax7 is used as a "driver" tube while the others are dedicated to the left and right channels.
Bill at MorningStar also recommended the TungSol blackplates or Telefunkens for the 12ax7's.
In the meantime, I've got a few 12ax7's that I can roll:
(1) Groove Tubes 12ax7-M
(1) Ei ECC83
(3) Jan Phillps 12ax7WA
(1) Jan GE 5751
various JJ's, Sovteks, EH with good numbers
By the layout of the unit, it appears that the 1 12ax7 is used as a "driver" tube while the others are dedicated to the left and right channels.