| 1st letter
- Heater rating |
A |
4V |
| B |
180mA AC/DC |
| C |
200mA AC/DC |
| D |
0.5 - 1.5V |
| E |
6.3V AC |
| F |
12.6V car battery |
| G |
5V |
| H |
150mA AC/DC |
| I |
20V |
| K |
2V DC |
| L |
450mA AC/DC |
| O |
Cold cathode |
| P |
300mA AC/DC |
| T |
7.4V; Misc. |
| U |
100mA AC/DC |
| V |
50mA AC/DC |
| X |
600mA AC/DC |
| Y |
450mA AC/DC |
| Remaining
letters give type(s) of device(s) |
A |
diode (excluding rectifiers) |
| AA |
double diode with separate
cathodes (excluding rectifiers) |
| B |
double diode with common
cathode (excluding rectifiers) |
| C |
Triode (excluding power
triodes) |
| D |
Power triode |
| E |
Tetrode (excluding power
valves) |
| F |
Pentode (excluding power
valves) |
| H |
Hexode/heptode (hexode
type) |
| K |
Heptode/octode (octode
type) |
| L |
Output tetrode, beam tetrode
or pentode |
| M |
Tuning indicator |
| N |
Gas filled triode or thyratron |
| P |
Secondary emission |
| Q |
Nonode |
| S |
TV sync oscillator |
| T |
Beam tube |
| W |
Gas rectifier |
| X |
Gas fullwave rectifier |
| Y |
Halfwave rectifier |
| Z |
Fullwave rectifier |
| Figures -
base + serial number |
1-10 |
Various side contacts,
octals, specials (exceptions are ECH3G, ECH4G, EK2G, EL3G, KK2G which
have octal bases) |
| 11-19 |
8-pin German octal |
| 20-29 |
Loctal B8G; some octal;
some 8-way side contact (Exceptions are DAC21, DF21, DF22, DL21, DLL21
which have octal bases) |
| 30-39 |
Octal |
| 40-49 |
Rimlok B8A |
| 50-59 |
B9G; Loctal B8G; Octal;
3-pin glass; Disk-seal; German 10-pin with spigot; min. 4-pin; B26A;
Magnoval B9D |
| 60-69 |
B9G; some submins |
| 70-79 |
Loctal Lorenz; wire submins |
| 80-89 |
Noval B9A |
| 90-99 |
B7G |
| 100-109 |
B7G; Wermacht base; German
PTT base |
| 110-119 |
8-pin German octal; Rimlok
B8A |
| 130-139 |
Octal |
| 150-159 |
German 10-pin with spigot;
10-pin glass with one big pin; Octal |
| 160-169 |
Flat wire submins; 8-pin
German octal |
| 170-179 |
RFT 8-pin; RFT 11-pin
all glass with one offset pin |
| 180-189 |
Noval B9A |
| 190-199 |
B7G |
| 200-209 |
Decal B10B |
| 230-239 |
Octal |
| 270-279 |
RFT 11-pin all glass with
one offset pin |
| 280-289 |
Noval B9A |
| 300-399 |
Octal |
| 400-499 |
Rimlok B8A |
| 500-529 |
Magnoval B9D; Novar |
| 600-699 |
Flat wire-ended |
| 700-799 |
Round wire-ended |
| 800-899 |
Noval B9A |
| 900-999 |
B7G |
| 1000- |
Round wire-ended; special
nuvistor |
| 2000- |
Decal B10B |
| 3000- |
Octal |
| 5000- |
Magnoval B9D |
| 8000- |
Noval B9A |
In these, the numbering scheme is the same as above but the figures and 2nd+
letters are swapped round, for example E88CC. However the ExxYY and EYYxx versions
may be completely different valves so it cannot be assumed that the one is simply
a high quality version of the other.
