Srosenberg - I'm kind of cheap when it comes to NOS tubes, so I hunt for bargains, but for tubes that are highly recommended.
The best I've found so far are Telefunken 12AX7 smooth plates (early 60's vintage) that had great specs. I managed to steal them @ $85 for the pair. I'm using Phillips labeled Amperex SQ white labels in the 6922 slot that I found for $120.
The 12AX7 tubes are the most critical... so place your initial emphasis on finding these first. Telefunken's are clear, fast & dynamic, yet still smooth and fatigue-free. In second place are Mullard CV 4004 Platinum's, which are a good all-around tube, but slower sounding with more emphasis in the lower frequencies when compared to the Tele smooth plates, which excel in the mid to high frequecies.
I have tried more expensive tubes (Mullard 10M Gold Pins) @ $800 for the pair, but I found them to be too slow and muffled for my tastes. Keep in mind, that system synergy (amp pairing, cables, room interaction, etcetera) plays the most crucial role in your systems sound, so the tubes I've found to work best for my system may not be optimal for your system.
