I have tried many different tube combinations and settled on the Amperex/Holland 12AU7's and Shuguang Black Treasure 6CA7's . Good extension at both ends , warm presentation , clarity with musicality and definition .
The Primaluna El-34's are a pretty nice tube in their own right . My second best favorite small tube is the RCA Blackplate ( I think that this is the correct name) 12AU7 .
For a little less money , this combination is quite nice also .
Caveat ... I am using the Primaluna Dialogue Premium Integrated amp . I don't think that there will be much difference between these amps concerning tube choices . I have owned the Prologue integrated as a reference .
Good Luck
The Primaluna El-34's are a pretty nice tube in their own right . My second best favorite small tube is the RCA Blackplate ( I think that this is the correct name) 12AU7 .
For a little less money , this combination is quite nice also .
Caveat ... I am using the Primaluna Dialogue Premium Integrated amp . I don't think that there will be much difference between these amps concerning tube choices . I have owned the Prologue integrated as a reference .
Good Luck