I own two Citation II’s that I use to bi amp Martin Logan SL3 electrostats. One was completely restored by Jim McShane about 12 years ago when he was still doing the rebuilds himself. He outfitted the main power tubes with EI-KT 90’s, which I now have in both units. They are now difficult to find. I’ve rolled most tube brands through the smaller 12by7a tubes on both units including Phillips, GE, Sylvania, RCA, the original HK supplied tubes, and JAN tubes. I’ve never laid hands on the CBS tubes, they sound interesting. The differences are more than subtle in my opinion, certainly different, your personal taste for the sound signature will define your favorite. I like the JAN tubes because they are so rugged and balanced. In my opinion, the use of high end audio caps and the choice of the larger tubes made a bigger difference. I had Jim install Musicaps, they were expensive but worth it. They were designed by the Engineer Robert Hovland, who no longer is associated with Musicaps. He now is associated with a nearly identical featured brand called Supercaps (Robert Hovland series). Jim also endorses V-caps, also a high end audio capacitor. They are crazy expensive. Jim also installed some unique photo flash caps in the power section, which he no longer is able to get. He indicated they were the best he had found at the time. I luckily purchased a second set as backups and will eventually install them in the other amp. I also purchased two extra sets of the EI KT 90’s for posterity and eventual replacement. There remains hope that the factory will start back up. The rumors were that NATO blew up the factory during the war. Others say the war simply caused the shutdown and demise of the factory. The soundstage from the Citation II’s when rebuilt is astonishing.
