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.
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.