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Blog posts of '2012' 'March'

WHAT MULLARD VALVES DOES MY EKCO RADIO TAKE?

Jose from Soller in Majorca contacted me today asking what valves his trusty Ekco needed and that he was searching for Mullard valves.  I told him that I would come and have a look and identify them for him but that I  would need a week's free board and lodgings - ha-ha, said he.    Realising I was on a 'no hoper 'with this approach, I sorted him out some valve data and then thought, well, it's about time we had another blog entry, so, here's my freshly prepared valve line up list for many Post War and well known AC, DC & universal mains Ekco radios:- 

RADIO VALVE LINE UP
EKCO A21 ECH35 EF39, EBL31 AZ31 EM34
EKCO A23 ECH35 EF39, EBL31 AZ31 EM34
EKCO A28 ECH35 EF39, EBL31 AZ31 EM34
EKCO AC64 AC/S2PEN VP4 2D4A PENA4 IW2
EKCO AC74 SP4 VP4 TDD4 PEN4VA IW3
EKCO AC76 FC4 AC/VP1 2D4A PEN4VA IW3
EKCO AC77 FC4 VP4B 2D4A PENA4 IW3
EKCO AC85 AC/S2PEN VP4 2D4A 354V IW3
EKCO AC86 AC/S2PEN VP4 2D4A 354V IW3
EKCO AC97 FC4 VP4B TDD4 AC042 TV4 IW4/350
EKCO ACT96 AC/VP1 FC4 AC/VP1 2D4A 354V PEN4VA IW3
EKCO AD36 SP13 HL13 PEN36C 1D5
EKCO AD37 VP13C SP13C PEN36C UR1C
EKCO AD38 VP13C SP13C PEN36C UR1C
EKCO AD65 VP13C SP13C PEN36C UR1C
EKCO AD76 VP13C SP13C PEN36C UR1C
EKCO AD77 VP13C SP13C PEN36C UR1C
EKCO M23 S4VA 354V PM24M
EKCO U109 UF41 UCH42 UBC41 UL41 UY41
EKCO U29 CCH35 EF39 CBL31 CY31
EKCO U49 CCH35 EF39 EBC33 CL33 CY31
EKCO U75 CCH35 EF39 EBC33 CL33 CY31
EKCO U76 UCH42 UAF42 UAF42 UL41 UT41
HEALING RADIO - NO, NOT THE AUSTRALIAN TYPE!

Ello peeps, well, I'm back from my travels and am in a good mood so, I thought I would share this radio related radio joke with you, anyhow, here goes............

An elderly couple are listening to a preacher on their Atwater Kent breadboard radio when the preacher tells the listeners "If you need healing today, I want you to place a hand on the part of your body you need healed, then place your other hand on the radio's output valve and you will be healed!"    The old man slowly places a hand on the power output valve then  inches his other hand  firmly down the front of his trousers.     The old lady, looked up from her knitting, narrowed her eyes, pondered for a moment and then sharply said  "Don't be so silly,  he said he could heal, not perform a miracle in raising the dead!"

Tee-heee, a good un I think!!!!!!!

Nearly as good as this photo of a Healing Scales radio from Australia which I covet greatly.

 

 

A PRIMER ON VALVE BASES - WHEN WERE CERTAIN TYPES INTRODUCED?

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

 

 

SIVCRED & THE COMMON VALVE OR CV NUMBERING SYSTEM
OK, previous blog entries have described the “3 Services” legacy valve numbering systems as well as the GPO numbering system and as we have seen there was little if no commonality. Something had to be done and in 1941 everyone agreed to use a common system of nomenclature known as the COMMON VALVE or CV numbering. The agreement was a bit of a compromise as it only applied to NEW valves so there would always be old system labelled valves kicking about in stores. 

However, a volte-face occurred in 1943 as the Navy kicked up a fuss, so all valve types were retrospectively given a CV number. And this is described in the Admiralty SOP A.F.O. 4683/44. However, this activity was not taken in a haphazard manner and there is a pattern to this retrospective action with CV500 – CV1999, CV2500 – CV2999, CV3500 to CV3999 indicating retrospective renumbering. A similar logical rule was applied where newly developed valves would be numbered in the CV300 – CV499 range and thence in the first five hundred of each thousand up to 9499.


There are many tables circulating on the internet that list commercial equivalents against CV numbers, however, the best and most complete version is the Services Index of Valves colloquially known as SIVCRED. I believe my pal Jeremy Harmer at The Virtual Valve Museum hosts some SIVCRED pages – why not go ava look at 

www.tubecollector.org

Below, I have just one drawing from SIVCRED which is rather sweet:-

 
 
 

THE CYRILLIC VALVE NUMBERING SYSTEM AS TRANSLATED FROM GOST 5461-59

Well, whilst researching this blog article I really could have done with my Dad here as his Ukrainian multilingual ability would have been most useful, honestly, how do you cope with a 33 letter alphabet?   But no,  I persevered and didn't even contact my pal Gary Skiba who could have helped as well.   Some of you may know Gary as the leading UK Leak guru - I'll certainly be bending his ear when my blog subjects turn to all things Leak, anyhow, I digress, for here is a 'little' primer on Cyrillic valve numbering systems.   Now none of you will have an excuse for not being able to read valveski (oops - Polish!!!!).

The Russian military Standard Operating Procedure for thermionic device numerication is documented in the 1959 issued GOST 5461-59.    The numbering system comprises of a four character system.  Thermionic devices MUST have a complete four character code,  however, where a  character is   not required  as a device descriptor then a dash should be included in it’s place.          On no account must the code ever be shortened from the prescribed four character code (or you will be sent to Siberia). 

 

The first (1o) character defines the usage for a device
гК
TX valve < 25 MHz
гЧ
UHF TX valve 25-600 MHz
гC
TX valve centimetric radar
гM
Modulator valve
B
High power rectifier
Cг
Voltage stabiliser
Cг
Current stabiliser
T
Thyratron
гг
Gas-discharge rectifiers
гP
Mercury gas-discharge rectifier
 Ф/ фзY
Photo-electronic device
Heater voltage (V)
Receiving valve
Screen diameter (cm)
Cathode ray tube
Д
Semiconductor diode
Л
Transistor
 
The second (2o)  character defines the electrode structure for a device
Д
Diodes
X
Double diode
C
Triode
з
Tetrode
Л
Power pentode & beam tetrode
K
Remote cut-off pentode
ж
Sharp cut-off pentode
B
Secondary emission pentode
A
Twin grid mixer & hexode valve
ъ
Pentode with one or two diode
г
Triode with one or more diode
E
Tuning indicator
й
Triodes with hexode, heptode or octode
H
Double triode
P
Double tetrode or pentode
ф
Triode - pentode
л
Rectifier
Type sequence number
Gas-discharge rectifier
г
Gas thyratron
P
Mercury thyratron
X
Cold cathode thyratron
пM
Oscilloscope tubes with electrostatic deflection
пM
Oscilloscope tube with electromagnetic deflection
пK
Cathode ray tube
Type  number
Semiconductor
 
The third (3o) character is a numerical descriptor
Receiving, picture, generator, modulator, stabiliser,
photo- electronic device, thyratron
Sequential number
Semiconductor
Characteristic letter
 
The fourth (4o) character defines the construction type and material for a device
-
Metal
Applicable to receiving & stabiliser valves
C
Glass
ж
HF glass, side leads
K
Ceramic
п
Miniature glass 19 & 22.5 mm
г
Subminiature > 10 mm
ъ
Subminiature 10mm
P
Subminiature 4 mm
A
Subminiature 6 mm
п
lock-in-key
д
Disc leads
A
Water cooled
Applicable to TX and modulator valves
ь
Air cooled
letter
Phosphor colour code
Applicable to CRT only
X
X = Average current (A)
Y = Reverse voltage amplitude (kV)
 Applicable to thyratron & rectifier valves
 
Post main code suffix (x-bis)
B
Military high reliability ruggedized valve
E
Military long life valve
й
Impulse trigger device
K
Vibration resistant ruggedized device
 
Current Regulators
[A]ь [V1-V2]
Current,  (A) = [A]; Voltage range, (V) = [V1-V2]
 
Wow, it’s a biggie this table, however, I have a few more interesting nuggets for you next. Russian and Chinese valves seem to be used in a lot of budget Chinese hifi these days    (the latter not so surprisingly!!!!)

First of all, here’s a Cyrillic to European letter conversion table:-

 
   
Using this you should now be able to identify what your Cyrillic valves equate to whatever language the envelopes are marked in. My equivalent table below – a first for the internet I think - has been populated with a European character set and relates the more commonly seen Russian & Chinese types to the ‘common all garden' US and European type numbers, 'Nice one Cyril!':-
 
European
US
Chinese
Russian
ECC88
6DJ8
6N23
6N23P
E88CC
6922
6N11
6N23P-EV
6SN7
6SN7
6N8
6N8P - 6CC10
6SL7
6SL7
6N9
6N9P
EF86
6267
6J8
6J32P
5687
5687
6N12
N/A
ECC40
N/A
6N1
6N1P
N/A
6AX7
6N2
6N2P / 6CC41
296A
2C51
6N3
6N3P / 6CC42
ECL82
6BM8
N/A
6F3P
EL84
6BQ5
6P14
6P14P
6L6
6L6
6P3P
6P3S
6V6
6V6
6P6P
6P6S
KT88
6550
6P27P
6P27P
U52
5U4G
5Z3P
5Z3S
5Y3
5Y3
5Z2P
5Z2S
GZ30
5Z4
5Z4P
5Z4S
 

 

THE GENERAL POST OFFICE (GPO) VT VALVE NUMBERING SYSTEM

Confusing or what, the GPO had their own Valve - Thermionic numbering system comprising of a sequence of numbers in range from VT17 to VT207.  Although this alphanumeric code followed the same form as the US Signal Corps one it was quite different.    I have produced a look up table that related GPO VT number with UK CV number and commercial equivalent numbers - a first for the internet I think.  Enjoy:-

GPO VT NUMBER CV NUMBER COMMERCIAL NUMBER
     
VT19 CV1612 VT9B
VT24 CV1636 LS5
VT25 CV1637 LS5
VT26 CV1600 CAT1
VT27 CV1601 CAR1
VT31 CV1638 4101D
VT33 CV1642 DER
VT34 CV1614 ES1500A
VT35 CV1615 ESU1500
VT36 CV1602 CAR4
VT38 CV1645 E133
VT40 CV1647 LS5B
VT46 CV1616 4104A
VT47 CV1603 4104B
VT50 CV1050 HL2K
VT52 CV1025 DET25
VT54 CV1618 ES250M
VT56 CV1648 4205B
VT57 CV25 4242A
VT58 CV1619 4212E
VT60 CV1605 4013C
VT61A CV1609 SW7
VT62 CV1606 CAT2
VT65 CV1649 E133
VT66 CV1650 LS5A
VT68 CV1651 G445
VT69 CV1652 P220A
VT74 CV1654 L2
VT75 CV1655 4019B
VT78 CV1656 LS8
VT82 CV1659 4022B
VT83 CV1660 LS7
VT86 CV1662 P215
VT87 CV1663 4021B
VT88 CV1664 4022AR
VT89 CV1665 DH
VT90 CV1732 ML4
VT91 CV1038 MHL4
VT92 CV1735 DC2/P
VT93 CV1666 P610
VT94 CV1667 LS5X
VT95 CV1668 4033L
VT98 CV1669 P625
VT100 CV1040 PX25
VT105 CV1673 HL2
VT106 CV1674 AC/52PEN
VT107 CV1675 N43
VT109 CV1677 PX25
VT111 CV1679 DA30
VT112 CV1680 PM202
VT114 CV1682 PENA4
VT115 CV1683 MP/PEN
VT119 CV1169 VMP4G
VT120 CV1688 4033L
VT125 CV1689 PA1
VT126 CV1690 9A1
VT127 (CV1187) D41
VT128 CV1692 AC/P
VT131 CV1168 PX4
VT133 CV1695 DDL13
VT136 CV1118 KT2
VT137 CV1081 4052A
VT138 CV1623 RG1-125
VT139 CV399 MH4
VT140 CV1166 LP2
VT143 CV1696 PM2BA
VT144 CV1371 PT6
VT145 CV243 4045A
VT146 CV1625 RG3-250
VT147 CV1697 X41
VT148 CV1698 A819
VT150 CV1699 SP41
VT150A CV1700 SP41
VT151 CV1701 XLO
VT152 CV1702 XP
VT153 CV1703 XW
VT154 CV1067 L63
VT161 CV1710 6C6
VT162 CV1711 6B7
VT163 CV1712 42
VT164 CV1713 EF8
VT167 CV1716 E1541
VT169 CV1717 4307A
VT170 CV1718 AC/TP
VT171 CV1719 U22
VT177 CV1720 XL 1.5
VT178 CV1721 XP 1.5
VT179 CV1722 A901
VT180 CV1053 EF39
VT181 CV1052 EL32
VT182 CV1723 V257
VT183 CV1724 5A/102D
VT185 CV245 4328D
VT188 CV1727 SP210
VT189 CV1128 GT1C
VT190 CV1728 WE262B
VT191 CV1628 GU8
VT193 CV1100 KTW62
VT194 CV587 DH63
VT195 CV1863 5Z4G
VT196 CV509 6V6G
VT199 CV124 807
VT200 CV1065 SP61
VT201 CV1056 EF36
VT202 CV1054 EB34
VT203 CV9 AL60
VT204 CV18 DET19
VT205 CV1630 ESP450
VT207 CV1091 EF50
WW2 GERMAN EIGANTUM VALVE CODES

Having now done the WW2 Allies valve numbering, it would be churlish to not include the other sides' rohren numbering system now wouldn't it?   Now let's see what's left still to do, oh yes, the CV system, the Cyrillic system and the GPO numbering system, phew, better get blogging and then we can get back to the story of Mullard - what would you all like next -  ground breaking  products in the 1950's, semiconductor manufacture in the 1950's or expansions and endowments (yes there's more!) in the 1960s - you choose - let me know using the comments function? 

 

KRIEGSMARINE & WERMACHT

These German Eigantum valves carry an alphanumeric code in the sequence: two letters, two numbers, one letter, two numbers.

First letter

R - Reichswehr (Defence) encompassing Wehrmacht  (Army) and Kriegsmarine  (Navy)

Second letter

D - Decametric wavebands
G - Rectifier (Gleichrichter) or diode
K - Cathode ray tube
L - Transmitting or Power
V - Amplifier (Verstärker)

First & second number

Heater voltage

Third letter

A - Cathode ray indicator
D - Dual anode
G - Rectifier or diode
H - Hexode
L - Speed modulation
M - Magnetron
P - Pentode
T - Triode

Final number

Power output (W) or rectifier maximum delivery current (mA).

 

LUFTWAFFE

These German Eigantum der RLM valves carry an alphanumeric code in the sequence: two letters, one number.

First letter

L - Luftwaffe (German Air Force)

Second letter

B - Cathode ray tube
D - Decametric waves
F - Special type
G - Rectifier or diode
K - Stabiliser
M - Magnetron
S - Transmitting, wavelengths > 1 M
V - Amplifier, wavelengths > 1 M

First  number

Heater voltage

THE PRE COMMON VALVE NUMBERING SYSTEM USED BY THE BRITISH ARMED FORCES

Having broken off from my historical diatribe on Mullard, here are a few useful snippets about the pre CV valve numbering system used by the British Armed Forces - here is an explanation of what the various alpha suffix codings used by the different service arms mean - now you'll at least be able to identify the valve type if not the type number:-

British Army

Comprises of an alpha coding which signifies the valve use or configuration followed by a numeric code that signifies valve.  The most commonly seen are listed below:-

ACR - Army  cathode ray tube
AR - Army receiving valve
ARD - Army receiving diode
ARDD - Army receiving double diode
ARH - Army receiving hexode
ARP - Army receiving pentode
ARS - Army receiving screen grid tetrode
ARTH - Army receiving triode hexode
ARTP - Army receiving triode pentode
AT - Army transmitting valve
ATP - Army transmitting Pentode
ATS - Army transmitting screen grid tetrode
AU - Army Rectifier
AW - Army Stabiliser

British Royal Air Force

Comprises of an alpha coding which signifies the valve use or configuration followed by a numeric code that signifies valve.  The most commonly seen are listed below:-

VCR - Valve cathode ray tube
VGT - Valve gas thyratron
VI - Valve indicating magic eye
VR - Valve receiving
VS - Valve stabilizing neon type
VT - Valve transmitting
VU – Valve rectifying

British Royal Navy

Comprises of an alpha coding which signifies the valve use or configuration followed by a numeric code that signifies valve.  The most commonly seen are listed below:-

NC - Navy cathode ray tube
NGT - Navy gas thyratron
NR - Navy receiving valve
NS - Navy stabilizing neon type
NT - Navy transmitting valve
NU - Navy rectifier

 

THE WW2 US ARMY SIGNAL CORPS VALVE NUMBERING SYSTEM

The US Signal Corps, used a numbering system of VT numbers, incidentally, the VT stands for Valve, thermionic – three electrode – a bit of a to do if you want to list a beam tetrode!!!! .  The military look up table MIL-HDBK-213A is required to decode the 289 valves identified in this manner.  However, for the ardent audiophiles, I have prepared this list of the most desired devices:-

VT4C = 211

VT66 = 6F6

VT74 = 5Z4

VT80 = 80

VT94 = 6J5

VT95 = 2A3

VT100A = 807

VT107 = 6V6

VT115 = 6L6

VT126 = 6X5

VT144 = 813

VT145 = 5Z3

VT217 = 811

VT229 = 6SL7GT

VT231 = 6SN7GT

VT197A = 5Y3GT

VT206A = 5V4G

VT244 = 5U4G