Some variants of the 6L6 valve are: 6L6, 6L6G, 6L6GA, 6L6GB, 6L6WGB, 5881 and 6L6GC. Some were even labelled with military specifications numbers such as JAN-6L6WGB and CV 2796. There may be probably more variants, even NOS ones. I refer only to the NOS types and not to the reissue types.
I did some comparison tests on some NOS Tungsol JAN-6L6WGB and NOS Teonex CV 2796 valves. The commercial number for a CV 2796 is 6L6WGB. The 5881 is also exactly the same as the 6L6WGB valve - some valves are marked with both these numbers on the glass tube.
Fortunately I had enough NOS ones of each in order to conduct comparison emission (Ia) tests with an AVO valve tester between the both types. For the purpose of this comparison I did not record the Gm figures. According to the AVO valve tester, the Ia has to be 54mA for a new 6L6 valve, to test 100%.
To my surprise all the CV2796 valves tested very high, between 64 to 68 mA whereas the Tungsol JAN-6L6GWB valves tested between 54 to 58mA. Both are so called military type valves with brown phenolic valve bases.
When I inspected the internal construction of the two types, the Teonex looked to me identical to the Tungsol type.
Apparently Teonex was a company in England that marketed and distributed different valve makes under its own brand. Maybe Teonex selected only high output valves to be marked CV 2796.
I did some comparison tests on some NOS Tungsol JAN-6L6WGB and NOS Teonex CV 2796 valves. The commercial number for a CV 2796 is 6L6WGB. The 5881 is also exactly the same as the 6L6WGB valve - some valves are marked with both these numbers on the glass tube.
Fortunately I had enough NOS ones of each in order to conduct comparison emission (Ia) tests with an AVO valve tester between the both types. For the purpose of this comparison I did not record the Gm figures. According to the AVO valve tester, the Ia has to be 54mA for a new 6L6 valve, to test 100%.
To my surprise all the CV2796 valves tested very high, between 64 to 68 mA whereas the Tungsol JAN-6L6GWB valves tested between 54 to 58mA. Both are so called military type valves with brown phenolic valve bases.
When I inspected the internal construction of the two types, the Teonex looked to me identical to the Tungsol type.
Apparently Teonex was a company in England that marketed and distributed different valve makes under its own brand. Maybe Teonex selected only high output valves to be marked CV 2796.
