bcowen
Headphoneus Supremus
And I have some RCA's labeled as Chatham. LOL!I prefer the sound of the Svetlanas from the 50's myself, especially the 1955 Navy issue. I like the mids a bit better than some of the later ones. I can tell no difference in sound between two from 1959 with the two numbering schemes.
I may have gifted one to Cowen so he might be able to address the sound as well. I also gave him a prized Melz from 1954 or 1956, I dealt with a lot of Russian tubes while filling out my collections.
Somewhere I also have some bottom getter tubes made by Chatham for RCA as best I recall. Friends are starting to work on tube comparisons and I provided twenty such tubes and the Chathams may well have been in there.
You gave me a 1958 Svetlana, but I only have one other to compare to from the late '70's IIRC (I'd have to dig it out to verify). I like the 1958 better...has more midrange detail and harmonic nuance and deeper, punchier bass. Not night and day, but enough to be worthwhile IMO for anyone searching these out. I still prefer the Chatham 6AS7G to either of the Russkies, and they still pop up every now and then for mostly sane prices. Wait....I have the pair of Amperex Made in England (or West Russia) Svetlana's too...forgot about those. No way of telling what year they are though since all the Svetlana markings are gone.
I've purchased a bunch of Foton 6N6P's for Folkvangr. Have full sets of both the square dimpled getter and the (usual) round UFO getter to give both a try versus the stock tubes (which are Reflektors). Just haven't had the time yet to compare them.