A PRIMER ON VALVE BASES - WHEN WERE CERTAIN TYPES INTRODUCED?
Posted by STEVE M on
Mama Mia! An e-mail from Vigata in Sicily enquiring about when certain valve bases were introduced. I know a valve dealer from Sicily you know, he's from Messina and ever such a nice chap but I digress........ There exists a whole raft of valve bases, however, I shall deal with only the most commonly seen bases and their dates of introduction in the following table:-
|
Year of Introduction |
Valve Base Type |
Descriptive notes |
|
1916 |
B4 |
Introduced by French valve manufacturer Duclos-Fivre |
|
1927 |
B4 + side screw |
Introduced for indirectly heated cathodes |
|
1928 |
B4 + top cap |
VHF/ UHF anode top cap connection |
|
1928 |
B5 |
An extra pin for the pentode |
|
1933 |
B7 |
More extra pins for the heptode |
|
1934 |
B9 |
More extra pins for the nanode and dual triode |
|
1934 |
Ct8 |
Philips side contact to stop competiton sales |
|
1935 |
5AA |
Acorn valve by RCA in the USA |
|
1935 |
IO |
International Octal introduced in the USA |
|
1935 |
7AA |
More acorn valves by RCA in the USA |
|
1937 |
B3G |
Introduction of TV boost diodes |
|
1938 |
MO |
Mazda’s independant Octal base is introduced |
|
1938 |
B8G |
Loktal introduced in the USA for military use |
|
1938 |
B9G |
By Philips for the EE50 and EF50 |
|
1939 |
B7G |
Introduced in the USA by Sylvania & RCA |
|
1947 |
B7G |
Brimar & Mullard use for the first time in the UK |
|
1948 |
B8G |
Mullard use for the first time in the UK |
|
1948 |
B8A |
Brimar & Mullard first UK use of ‘Rimlock’ |
|
1948 |
B9A |
Introduced in the USA by Sylvania & RCA |
|
1951 |
B9A |
Mullard use for the first time in the UK
|
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- Tags: B9A, OCTAL, VALVE BASES