invalid and @jackd, IME your system is no stronger than the weakest link. OTOH, music is very personal, so weakest link is subjective. So, reviews of tubes are going to vary based upon the neutrality of the system, and the predilections of the user. I tend to error on the side of neutrality, or what I perceive as neutrality. I judge neutrality based upon music without electrical power as once you introduce electricity there is no way to actually know how an electric guitar or synthesizer is supposed to sound. OTOH, with a neutral system you, if you know cymbals for instance, you can determine the manufacturer. I don't know cymbals, but those who do can differentiate on neutral systems I'm told. Anyway, old tubes, 6SN7, or 7N7s historically have been disappointing in my system. The E-6SN7s by Linlai sound pretty good. 1964 and older 6H8C Soviet tubes sound the best. The DS2 has various output capacitors. Mine had V-Caps, ODAMs, bypassed with CuFT's, which are very transparent, aka accurate. All of this will impact the sound of the tubes. Ultimately what I like may not be worth anything to someone looking for different attributes and neither of us is wrong because music is personal. I know nothing about newer versions of Vandersteen speakers, but older ones buried details, IME, but while I hate that about them, others love it, neither is right or wrong, we are just listening in ways that appeal to us. The end result is pretty hedonistic IMO, so what another wants is subjective and is therefore only right or wrong in the ears of the particular listener matters. That said, the 1964 and prior 6H8C tubes with the square getter, IME are awesome. I haven't revisited my NOS tubes since several critical upgrades have been made to my system, but I am not expecting any surprises. This opinion was worth every cent you paid for it.