EH is made by the New Sensor Corp, the New Sensor corp., also bought the Svetlana name. SED winged C tubes are made at the original factory that Svetlana's were originally made at. So they are actually the real svetlana and tubes that say Svetlana now are the fake Svetlana el34. However, New Sensor does make some decent tubes, like the tung sol 12ax7's and some others. Sovtek was already an established company when New Sensor took over. So the answer to your question is not really , each brand still carries it's own variation of the same tubes.I believe one of the EL34's by EH was the same as a sovtek but that may have changed through the years. Sovtek has remained pretty much unchanged by the New Sensor takeover and they make "some" decent tubes. 5881's and some of there 12ax7 types are decent, they are fairly rugged tubes.