READOUT TUBE BASES & SOCKETS

BASE
TYPE
Number
of Pins
Pin
Diameter
Pin Circle
Diameter
Pin
Spacing
Alignment
Method
Aliases,
Sockets & Notes
B7D 7 0.45mm (0.018") 9.53mm (0.375") 45° Pin Gap
(90°)
 
B7G 7 1.02mm (0.040") 9.53mm (0.375") 45° Pin Gap
(90°)
Pico, 7‑Pin Miniature, E7‑1
K8A 8 2.36mm (0.093") 17.45mm (0.687") 45° 7.82mm (0.308") dia. Splined Center Spigot Octal, A08, A8, B8‑21, I.O. (Intermediate-shell Octal or International Octal), K, O, SK8
B9A 9 1.02mm (0.040") 11.9mm (0.469") 36° Pin Gap
(72°)
Noval, 9 Pin Miniature, Pico 9, E9‑1, E9‑68
B9E 9 1.02mm (0.040") 17.45mm (0.687") 36° Pin Gap
(72°)
Novar, 9‑17, E9‑75, E9‑76, E9‑88, E9‑89
TO‑100 10 0.5mm (0.020") 5.84mm (0.230") 36° None/
Pin Gap (72°)
a.k.a. "10‑Pin TO‑5". Known readout tubes with this base have 9 wires & a gap, but sockets have 10 contacts.
B9A+ 10 1.02mm (0.040") 11.9mm (0.469") 36° Pin Gap
(outer circle: 72°)
9‑pin outer circle w/ gap & single pin in exact center.
B10C 10 1.02mm (0.040") 11.9mm (0.469") 34° Pin Gap
(54°)
Decal, Dekal. I have found several apparently erroneous references to this same base as B10B and even one as B10A. B10B exists but is different. I haven't found any info on B10A.
B11A 11 2.36mm (0.093") 19.1mm (0.750") 32.7° 7.8mm (0.307") dia. Splined Center Spigot Sub‑Magnal, B11‑88
U11 11 2.36mm (0.093") 27mm (1.063") 32.7° 7.8mm (0.307") dia. Splined Center Spigot Magnal, B11‑1, B11‑33, B11‑66
SK‑116 11 0.45mm (0.018") 9.4mm (0.370") 30° Pin Gap
(60°)
RTS‑3, SK‑116A, SK‑118A, SK‑119A, TSM‑11P
M‑117 11 ?         Said to be socket type for CD16A tube. Tube has bakelite shell.
M‑121 11 ?         Said to be socket type for CD46 & CD67 tubes. Used with matching "backing" (?).
M‑126 11         = SK-116 ? Said to be socket type for CD36A tube.
M‑131 11 ?         Said to be socket type for CD16B tube.
B12A 12 2.36mm (0.093") 27mm (1.063") 30° 15.5mm (0.610") dia. Splined Center Spigot Duodecal, B12‑43, TSB‑12P, VH33/1201, VH33/1202
B12C 12 1.02mm (0.040") 19.1mm (0.750") 27.7° Pin Gap
(55.4°)
Duodecar, Compactron, 12 CS‑B, E‑70, E‑74, SK12
B12E 13 2.36mm (0.093") 27mm (1.063") 30° 15.5mm (0.610") dia. Splined Center Spigot S0‑22. 13th contact is 6.35mm (0.250") anode cap on bottom of spigot. One source reports that the "B12E" designation refers to the very different (subminiature) "Nuvistor" tube base. Another source reports Nuvistor base designations as Twelvar, NV5, NV7, and NV12.
B13B 13 1.02mm (0.040") 16.7mm (0.656") 25.7° Pin Gap
(51.4°)
13‑Pin All Glass, 13‑17, 2422 505 00001, 2422 505 00002, B8 700 67, B8 700 69, B8 702 28, HSK‑106, HSK‑112, M‑111 ?, RTS‑1, RTS‑2, RTS‑6, RTS‑8, RTS‑9, SK‑106, SK‑109, SK‑112, SK‑120, SK‑124, SK‑125, SK‑128, SK‑130, SK‑135, TSB‑13P, VH13/131
B13D 13 0.45mm (0.018") 9.53mm (0.375") 25.7° Pin Gap
(51.4°)
13‑Pin Subminiature
SK‑176 13 0.51mm (0.020") N/A (oval) Various Off-center key pin inside main perimeter Subminiature Oval, RTS‑32, RTS‑33, SK‑178
SK‑111 13 1.02mm (0.040")       Burroughs Pixie, SK‑111‑H, SK‑111‑V, HSK‑111, VSK‑111.
13 Pin Russian 13 2.36mm (0.093") ? ? 27.7° ?? dia. Splined Center Spigot  
RTS‑11 12, 13 or 14 1.02mm (0.040") Outer 10: 12.7mm (0.500"), Inner 4: 5.4mm (0.212") Outer 10: 36°,
Inner 4: 90°
Pin Geometry RTS‑14, RTS‑18, RTS‑47, RTS‑48, RTS‑49, RTS‑50
SK‑136 14 1.02mm (0.040") N/A (oval) Various Pin Geometry Oval Nixie, 30254, 30256, 55705, M‑128 ?, PL31A‑P (ПЛ31А‑П), RTS‑4, RTS‑10, SK‑144, SK‑169, TSR‑11P
14 Pin Russian 14 1.0mm (0.039") 18mm (0.709") 24.5° Pin Gap
(41.5°)
PL31‑2V (ПЛ31‑2В). Central hole needed for tube nipple = 5mm dia.?
TSB‑14P 14 1.02mm (0.040") 20mm (0.790") 22.5° ?? dia. Splined Center Spigot & 2 Pin Gaps (45°, each oriented 90° from the key spline) Known tubes with this base type include CD11, CD14, CD94, GR‑201 and GR‑211.
B14A 14 2.36mm (0.093") 44.5mm (1.750") 25.7° 19mm (0.750") dia. Splined Center Spigot Diheptal, B14‑38, B14‑45, SK‑117
SK‑207 14 0.45mm (0.018") N/A (grid) various; two center rows 2.29mm (0.090") Grid RTS‑44. This pin grid version has up to 12 pins in the two center rows and typically 2 (could accommodate 4) pins in the outboard "wings". Actual lead configuration exiting bottom of these tubes does not match description; described layout is achieved by use of insulating spreader/standoff included with tube.
Euro Grid 14 or 16 0.6mm (0.025") N/A (grid) 2.54mm (0.100") Grid 14‑Pin All Glass Miniature ?, 16‑Pin Miniature ? 55702. This pin grid base version has 10 pins in the two center rows and typically 4 (rarely 6) pins in the outboard "wings".
B12E+ 15 2.36mm (0.093") 27mm (1.063") 30° 15.5mm (0.610") dia. Splined Center Spigot 13th contact is 6.35mm (0.250") anode cap on bottom of spigot. 14th & 15th are wire "flying leads" with color-coded sleeves.
SK‑182 16 0.76mm (0.030") 11.4mm (0.450") 21.5° Pin Gap
(37.5°)
16‑Pin Mini Round, IEH‑866, IEH‑868, SK‑183, SK‑184, SK‑185, SK‑193, SK‑194, SK‑195, SK‑196, SK‑197, SK‑198, SK‑199, SK‑200
B17A 17 1.02mm (0.040") 18.2mm (0.718") 20° Pin Gap
(40°)
B17, 17 Pin all‑glass, 35708, 35709, HFD 13045, HFD 13534, SK‑174 ?, VH26/1703. Some B17A based tubes (those without an evacuation/fill nipple extending between the pins) will also fit in B26A and B27A sockets.
SK‑137 17 1.02mm (0.040") 34.9mm (1.375") 20° Pin Gap
(40°)
RTS‑5
B26A 26 1.02mm (0.040") Outer 17: 18.2mm (0.718"), Inner 9: 11.1mm (0.437") Outer 17: 20°,
Inner 9: 40°
Pin Gap
(outer circle: 40°)
S0‑42, SK‑100, SK‑131, SK‑174 ? B26A based tubes will also fit in B27A and some B17A sockets. Known B26A based readout tubes (but not counter tubes) need no connections to inner pin circle, allowing use with B17A sockets if they fit.
B27A 27 1.02mm (0.040") Outer 17: 18.2mm (0.718"), Middle 9: 11.1mm (0.437"), Center 1 Outer 17: 20°,
Middle 9: 40°,
Center 1
Pin Gap
(outer circle: 40°)
27‑18. B26A and some B17A based tubes (those without an evacuation/fill nipple extending between the pins) will also fit in B27A sockets.


Notes:
1. If a base designation is not known, a socket part number or made-up name is used instead as a temporary placeholder, shown in italics.

2. The terms "Pin" and "Pins" as used here include pins, wires, anode caps, flying leads and any other forms of electrical contacts.

3. The table is sorted in ascending order by number of pins.

Definitions -
BASE: The part of an electron tube which contains most or all of its electrical contacts. Also the primary part by which electron tubes are physically held in place in the equipment which use them. A tube base may be an integral part of the glass structure of the tube envelope, or a shell fastened to the glass envelope made of plastic, metal or other material(s). The specifications associated with a base designation refer primarily to the configuration of electrical contacts, but often include other attachment and/or alignment details. Somewhat confusingly, in German tube bases are called "Sockel", and similar terms such as "sokkel" and "sokler" are used in Norwegian and other European languages. Other terms include "culot" or "socle" (French) and "huls" (Dutch?).

SOCKET: The device which connects most or all of an electron tube's electrical contacts to the cicuit wiring or printed circuit traces of the equipment which uses it, and physically holds the tube in position in the equipment. In England, where electron tubes are known as "thermionic valves" or simply "valves" for short, sockets are naturally called "valveholders". In German, sockets are called "fassung" (singular) or "fassungen" (plural). In French, socket = "support".

References:
Electron Tubes & Valves Data - Figures and Outlines  A page from Franz Hamberger's KyteLabs InfoBase.
Sokkel oversikt radiorør  A page from the Norwegian Historical Radio Society. (No, I don't understand Norwegian!)
Tube bases  A page from Åke Holm's www.tubedata.com.
Tube sockets  Another page from Tubedata.
Tube Bases  One of Frank Philipse's Electron Tube Pages.
Zero Wing All your base are belong to us.
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