Tube question: any sonic difference in 6SN7 vs 6H30 vs 6H80 in the amp's signal position?


Tube question: any sonic difference in 6SN7 vs 6H30 vs 6H80 in the amp's signal position?

Reason I ask is I just received a new-to-me BAT VK-55, and it has 6SN7 tubes in the signal positions, which is also what the manual references as the right tube, but the Stereophile review, in the specs page, references 6H80s in the same position, and VK-55SE uses a pair each of 6SN7s and 6H30s.  

BAT output tubes are 6C33C-Bs, so no tube rolling here, as it appears Solvtek is the only manufacturer of this style tube. I am wondering what if anything I can do with the signal tubes to help improve clarity of higher frequencies?
128x128thosb

 It is a different version of the amp. You can't replace 6SN7 tubes with 6H30 ones. They are not interchangeable. 


The 6SN7 is a better sounding tube as its easier to find examples that have lower microphonics. IOW the 6SN7 was designed for audio.

BTW the 6C33 power tube has been out of production and the plant that made them dismantled for about 19 years.