Saturday, February 20, 2021

TRANSISTORS, CV Designations - UK Military Specification for Germanium Transistors

CV Transistors are UK military spec valves, transistors and diodes (CV stands for common valve, as it predates semiconductors).  CV transistors were made by several different manufacturers on contract and produced to the UK military's specifications.  These can be, and quite often are, common commercial transistors made to military specification and renumbered.

Here are a few pedal-friendly transistors with well-known counterparts.   I may expand on this if I find more information.  

Like most things, I am by no means an expert - this is primarily for my own purposes, so please don't get too mad at me if you're a CV transistor expert and I have somehow misinterpreted something or made a mistake.  That being said, do feel free to leave me a comment.  This guy is an expert if you are interested in more information.


CV TRANSISTOR CODES

The codes can vary, and this is not a definitive collection of every possible code and variation - but here's a very loose and abridged guide.  

Usually, there will be three parts.  Specification, designation, date.

Hypothetical example:  A Mullard OC45 made to the K1001 specification for the UK in the first week of 1969 might have a code that looks something like this.

KB/D 6901
CV5105

CV TRANSISTOR SPECIFICATION CODE

There are two parts, the first for the specification, the second being the manufacturer (see the next heading re factory codes).

KB/XX

First letter

K    Specification K1001 or K1006

J    JAN or MIL-spec

Second letter

B    UK authority

U    US qualification

D    Australian

X    Director of Electronics Research and Development


FACTORY CODES

Mullard          D, DA, DB, DC, DE, DF 

Valvo             DP

Newmarket    CO

STC                F, FB, FC, FD, FDA, FE, FF


DATE CODE

Usually made up of four numbers, the first two being the year, the second two being the week of manufacture.   example:  6901 is the first week of 1969.


GERMANIUM CV TRANSISTOR EQUIVALENTS


MULLARD

CV2389    OC71

CV2400    OC71

CV5105    OC45

CV5337    OC73

CV5416    OC84

CV5439    OC75

CV5457    OC70

CV5710    OC44

CV5711    OC77

CV5712    OC71

CV5713    OC72

CV5813    OC123

CV7002    OC72

CV7003    OC44

CV7004    OC45

CV7005    OC71 (tin cans sound the same as NKT275, analogman)

CV7006    OC72

CV7007    OC77 

CV7111    OC139

CV7112    OC140

CV8314    OC76

CV8315    OC44

CV8316    OC45

CV8344    OC71

CV8435    OC140

CV8346    OC77

CV8389    OC71

CV8440    OC72

CV8724    OC83

CV8756    OC122

CV8966    OC139

CV9259    OC83

CV9447    OC77

CV9778    AC127

CV9779    AC128

CV9927    OC71 (advanced spec)

CV9928    OC44 (advanced spec)

CV9797    OC83 m.pr

CV10061    OC141

CV10675    AC176

CV10809  OC71


NEWMARKET

CV5445     NKT203

CV8559      NKT223

CV8765      NKT213

CV8794      NTK226

CV9190     NKT271

CV9372      NTK218

CV10855    NKT228

CV11170    NKT216

CV11175    NKT210


TEXAS INSTRUMENTS

CV7376      ACY17

CV7002      2G382  (also equivalent to OC72)

CV10164    2G387

CV10394    2G382


GET

CV7009    GET110

CV8607    GET113



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