Sovtek and Svetlana tubes are definitely good value for the money. I have owned no less than 8 Audio Research amps and I have only 1 tube blow out on me since I never run the bias rich. 50-55mA instead of pushing 65.
There are other ways to get richer sound and snappy bass than just biasing up the power tubes (eg. choice of coupling caps and making sure the diff amp tubes are fresh, and adjusted for symmetry with the trimpots)
I still remember fondly the conversations with Leonard and how he got me started with Inifinicap for my old Audio Research amps.
If cost were no object for this project, (hopefully sometime later), I'd be using V-cap teflon 0.22 - 0.33uF for the coupling caps (yes they are *that* good). Anything larger simply wont fit.
My next choice would be Jenseon oils but after having a few oil leak incidents I'd rather stick to the cheaper (but metal casing so use extreme caution) k40y9. Auricaps and Dynamicaps will fit easily, a few notches above the Relcaps, but not enough of an improvement to justify all the work esp on this amp IMO. Too many caps to replace.
All the above have leads which will not fit into the solder holes, you will need to do a 90 degree bend of about 2-3mm of the leads and solder them parallel to the pad. Also be EXTRA gentle and careful not to damage the traces when you are extracting the old caps.
The large can capacitors are always Sprague or Mallory or Cornell Dublier. Easy to swap out if you can find them in stock at Allied or Digikey or Mouser. Buying from Audio Research would be fail-safe of course.
