My Cayin KT88 had originally Shungyang tubes. Good, but nothing special. I tried the Sovteks KT88s and they were lifeless and thin sounding. I tried the Electro Harmonix and they were a mediocre match, too much treble and not enough bass. The were very powerful though.
Then I got me the Tungsol 6550 reissues. They clearly outperform anything else, and this is what I am using. In triode mode for classical and ultralinear for Jazz and Rock music. I suppose they would be a good match for your amp as well.
Then I got me the Tungsol 6550 reissues. They clearly outperform anything else, and this is what I am using. In triode mode for classical and ultralinear for Jazz and Rock music. I suppose they would be a good match for your amp as well.