New Tubes

500 hours for 12AX7's is barely broken in. They are capable of 5000 - 10,000 hours. I had 60's Fisher tube gear with the originals still installed, working and sounding fine.

What he said. However, nothing to stop you rolling the tubes. NOS (or used from good dealer) Telefunkens would be a good place to start.

Most gear today is voiced with JJ or EH, both are good stable valves. I don't think really good NOS valves will sound much better. This unit uses WiMa caps they have a sound more so than the actual valve. Both are very neutral, JJ or EH and Wima. That's my take on what the inside looks like. No fancy resistors, or parts, it's not point to point it's not all crammed together either.

I wouldn't spent too much on valves unless (like me) you use 12AX7 as a main valve in a lot of your gear. I keep good 12AX7s handy.. I personally match my valves. I'm way to picky. But my Macs and Cary's both sound very special because of it..

Blackburn (Mullard)
Telefunken
Amperex
Valvo
Mazda
RCA (only confirmed BP)
Solvex (W) black plate (BP)
GE NOS BP
Tungsram

New Stock

Golden Lyon
PSVANE
JJ
EH

Just about in this order, GE and Solvex can swap spots.

Regards