Audio Aero Capitole Amp

This is not the answer you have asked for, but it may be of some help:
Good 6SN7s are MUCH more important than cones in a Capitole amp. I prefer Sylvania JAN 6SN7WGTA. Others like NOS TungSol or the european equivalent tubes.
It also pays to roll the output tubes. I prefer JJ E34L and Gold Lion KT-88 from current-production tubes. They do make a huge difference.
IME Herbie's Isocups do a great work of isolating tube amps from external vibrations (better than BDR cones IMS).
Enjoy your amp

Caspuza, If you like the JJ E34 tubes, try the JJ 'Blue Bottle' Tubes. They work well im my Capitole. Yes, I agree that starting with good tube rolling is best.

Unclejeff, My amp came with Billington Gold 6sn7gt, JJ E34L and STA (Selected Tube Audio) 6550c tubes. Were these the tubes that the Capitole most likely came with when new? Which of these tubes would you recommend me rolling?

Replace the stock JJ tubes with Svetlana 'winged C' or the JJ Blue Bottles. Instead of the 6550 tubes, try KT 88 tubes, again Svetlana are a good beginnng.

The 6sn7 tubes are a bit more work, but you can do much better than the Billington tubes, or so I hear. I am currently using some Sylvania NOS tubes.

This amp is really different and most tube dealers don't have experience with them---especially with an amp that is running this combination of tubes.

The most reputable dealers will make suggestions but will concede they have not precise experience with this amp.

unclejeff, do you have a tube dealer that you could recommend?