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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