WHAT ARE SOVTEK TUBES?
Sovtek is a brand, not a factory. Either these are Russian NOS tubes, simply rebranded, or they are new made tubes from the REFLECTOR FACTORY in the Ukraine, Russia.
REFEECTOR tubes are sold under a range of brands, but in the end it is all from one factory. Brands seen to far are: New made Tung-Sol, Mullard, Electro Harmonix, Svetlana S-Logo and Gold Lion. So when buying a SOVTEK you get either a NOS tube, or a REFLECTOR tube. The NOS are often from old Reflector stock, but not always. Most of the new production Sovteks are a tube of it's own, and are not available at other brands.