I just got mine and I'm using it with Bellari phono stage with a NOS 1968 Mullard/Brimar,a Clearaudio Emotion table with an Aurum Beta S cartridge, and my 15 year old Harmon Kardon Sixty's. I immediately replaced the stock EL-34's with the new JJ Kt-77. The sound was pretty impressive, but there was a pretty significant humm. I replaced the O.E.M. 6N1P's with Svetlana Wings and the hum disappeared.The sound is now first rate.Huge soundstage,great depth,and crytal clear.My question pertains to the fact that the factory 6N1p's were numbered 1-4. The Svetlanas were not. Is this a concern.Any info. on this would be greatly appreciated.