Did Svetlana change hands?

The Svetlana brand name is owned by New Sensor Corp which also owns the Sovtek label. The current production Svetlana tubes are made in the Sovtek factory and are not nearly as good as the original Svetlana branded tubes. The good news is that the original St. Petersburg factory which used to make Svetlana is now in production under the SED name with the Winged C logo. If the tube does not have a Winged C on it is made by Sovtek and is a Svetlana in name only.

AND....I have two quads of the Winged C in my integrated amp and I like them very much!

Yes, to get the former "Svetlana" quality, you now have to buy "SED" tubes. The name "Svetlana" no longer corresponds to production of the old Svetlana factory. This adds unnecessary confusion and is very unfortunate. I wish the new owners had not chosen to re-introduce the name given they were not using the same factory and designs.

Go to the stereophile website where you will find a detailed explanation similar to Infinitebaffle's. It may not be confusing to "proffessional buyers" but it sure is to me!

I don't think any of this information is totally correct. It is true that the "winged C" logo is placed on the ones sourced from SED. I believe this was the original logo, but I'm not sure.

The other logo (hard to describe) in used on the ones sourced from New Sensor. Despite all this, the tubes look identical to my eyes. The bases, the inards, etc. To claim they are not the same designs is incorrect, I believe. Sonically, I did not hear any real difference between either tube. I think all of them, regardless of which factory they originate from, have quality control less than ideal.