Seems to me that your equipment just needs a few adjustments by someone that knows tube circuits. Small signal tubes usually last a very long time in a preamp or amplifier and most new production 5AR4s should work fine in any amp (some amps may need a slight modification or two).
For sale is a pair of 1980s? (Klipsch has no record of dates for LSIs serial #s) La Scala Industrial with refinished (see pictures) cabinets.
Due to the nature of the speakers and the timeline of the cabinet modifications (more below) it is really hard for me to put a condition rating on these...
The mystery of this amplifier continues to become a little clearer, it has a switch to select diode or tube rectification and I got it sorted with some help. It is working in both positions and with just one 5U4G in the PT is running around 125.
Have some 5Y3GTs and 5V4GAs on the way to try.
Another update on this amplifier.
When I started using it back in January I noticed the power transformer was running very warm and I ended up putting my SET amp back in because well it's my favorite amp. Completely forgot about the PT issue and I recently put some La Scalas together and have...
Direct quote from bottom of first paragraph here:
He does post a lot of nice pictures, if there is a prize for posting the same pictures a million times I think he has a slight lead over Sgt Shultz on AK.