Tube socket
Summary of base details

Tube socket

Section Title: Summary of base details
Table Section Text: None

Common Name	Standard Name	Other names	Base Pins	Pin Layout	Pin thickness	Specification	Period	Examples	European / Pro Electron numeric range

Pee-Wee	B3A	US Pee Wee 3p	3	08.7mm triangle with pins 1&3 closest	2.36mm	1937 -	ZA1004

Mazda subminiature	B3G	European special all-glass miniature	3 (+top)	06.0mm line with 3mm spacing	1mm	Mazda	1937 -	D1, EA50

European 3-pin	H3A	British 3-pin, Eu-3 (or B4, ignoring pin 4)	3	16mm isosceles triangle, greatest distance between pins 2 & 3	3.2mm	1920s to early 1930s (superseded by Octal and P8)	RE4120, 1832

UV4	B4B	WD-4-Pin	4	09.8mm rectangle with large pin 2 (usually anode)	2.3mm x3 3.1mm (pin 2)	1914 - 1920's (superseded by UX4)	WD-11

UX4	U4A	American 4-pin base with or without bayonet pin	4	11.9mm rectangle with thicker pins 1 & 4. Superseded the UV4 base	3.2mm (pins 2&3) 4.0mm (pins 1&4)	A4-10	1920s - 1930s (mostly superseded by Octal, but still used for some currently produced directly heated triodes)	A-P Oscillator (1920), 2A3, 300B, B405, X99, WW313A (1938), 866A

B4	A4A	British 4-pin, A4, European 4-pin	4	16.25mm kite	3.2mm	1915 to early 1930s (superseded by Octal and P8)	B405, BL2, R-type

UY5 UX5	U5A B5C	US 5-contact American Small 5-pin, USS5	5	19mm (3/4") circle, 3x60° between pins 1,2 and 4,5,1, 2x90° between pins 2,3,4	3.?	A5-11	1920s	UY227, 2E22, 1D4, 49, 807

B5	O5A	British 5-pin, European 5 -pin, Europa	5	16.25mm kite; B4 with central 5th pin added a B5 socket will accept European 3-pin (H3A) and 4-pin (A4A) tubes	3.2mm	1928 to early 1930s (superseded by Octal and P8)	B443

UX6	U6A	US 6-pin	6	19mm (3/4") circle, 6x60°	3.2mm x4, 3.9mm (pins 1 & 6)	1930's (superseded by Octal)	1F6, 2A5

B7	M7A	British 7-pin	7	23.1mm x 18.2mm oval	3.2mm	1930s (ultimately superseded by Octal)	AC3/Pen, TDD4, AL60, 18013

UX7	U7A	US 7-pin small	7	19mm (3/4") circle, 3x52°,4x51°	3.2mm x5, 3.9mm (pins 1&7)	1930's (superseded by Octal)	2B7, 6A7

Miniature 7-Pin	B7G	Miniature, Button, Mi-7	7	09.53mm (3/8") circle, 6x45° then 90° between pins 7 & 1	1.016mm	IEC 67-I-10a	1939 - present	1S4/DL91, 6AQ5, 6X4	90-99, some 100-109, 190-199, 900-999

Transcontinental	P8A	P-Type, Ct8, Philips 8, Side-contact 8	8	29.5mm circle of side-contact pins, 3x30° (pins 1-4), 5x54°	Side-contact	Philips	1930s	AL3	1-9 usually

Octal	K8A	IO, International Octal, A08, American octal base, Oc-8	8	17.45mm (11/16") circle, equal 45° spacing, 7.8mm spigot	2.36mm	originally: RCA IEC 67-I-5a	1935 - present	6CA7/EL34, 6L6/5881, 6SN7, 6V6GT, KT63/KT66/KT77/KT88/KT90, 6550, 7591	3G, 30-39, 300-399

Mazda Octal	K8B	MO8, Octal-8 GB, MO	8	18.5mm circle, 55,5° between pin 1 and 8, 43,5° between the other pins, 8.7mm spigot	2.36mm	Mazda	1938 - ? (short-lived)	ARP12, AR8, SP42, ATP4

Loctal	B8G or B8B	8-pin Loktal, Lo-8, Locking Octal	8	17.45mm (11/16") circle, equal 45° spacing, 6.7mm spigot	1.3mm	Sylvania	1939	1LN5, EF22, ECH71	20-29 and some others

Rimlock	B8A	European 8-pin Miniature base, Ri-8	8	11.5mm (0.453") circle, 45°	1.015mm	IEC 67-I-11b	1940s quickly edged-out by Noval, etc	6CU7/ECH42,EL41	40-49

Loctal-9pin	B9G	9-pin Loctal, Lo-9	9	21.0mm (13/16") circle, equal 40° spacing, spigot connected to can	1.3mm	Philips	1938 announced Sept. 1938 and available to Pye; general availability early 1939.	EC52 EF50 EF54 EL60	50-60 with some exceptions

Noval (Miniature 9-pin)	B9A	American Small Button, Button 9-pin	9	11.89mm (15/32") circle, 8x36° then 72° spacing between pins 9 & 1	1.016mm	IEC 67-I-12a JEDEC E9-1	1948 - present (still very popular)	12AX7/ECC83, 6BQ5/EL84	80-89, 180-189, 800-899

Magnoval	B9D	9	17.45mm (11/16") circle, 8x36° then 72° spacing between pins 9 & 1	1.27mm	IEC 67-I-36a JEDEC E9-23	1960s-1970s died out when TVs went fully solid-state	E55L, ED500, PL504	500-599

Novar	B9E	9-pin compactron	9	17.45mm (11/16") circle, 9x36° then gap between pins 9 & 1 Note: Novar sockets can be damaged by inserting Magnoval tubes	1.02mm	JEDEC E9-65 JEDEC E9-89	1959 - never very popular	6JF6, 22JG6A, 7868

Decal	B10B or B10C? often incorrectly stated	Dekal	10	11.89mm (15/32") circle, 9x34° then 54° gap between pins 10 & 1	1.016mm	IEC 67-I-41a JEDEC E10-61	1960s - 1970s	PFL200, ECC2000, ECH200, PCF201	200-299 2000

Decar	B10G	Dekar	10	11.89mm (15/32") circle as Noval, with additional center pin	1.016mm	Sylvania JEDEC E10-73	Mid-Late 1960s	6C9, 17C9

Sub-Magnal	B11A	Magnal, B11	11	17.45mm (11/16") circle as Octal	1.27mm	RCA?	1940s to present

DuoDecal	B12A	Duodekal, B12	12	27mm (1.063") circle, 30° angles	2.36mm	B12-43	1950s - 1970s	DG7-31, E1T, MW61-80

Duodecar	B12C	12-Pin-Compactron, E12-70, E12-74	12	19.1mm (3/4") circle, 11x 27.7° then gap between pins 12 & 1	1.02mm	E12-70(T9) E12-74(T12)	1960s - 1970s	1BY2, 6BD11, 12BT3

Nuvistor	B12K	Twelvar E7-83, E12-64, E12-65	12	11.2mm circular envelope with mixed-spacing field of pins	<1mm	IEC 67-I-17a JEDEC E12-64(5/12)	1959 -	7586, 6DV4, 6DV8, 13CW4

Sentence(s)

The Duodecar B12C base has 12 pins in a 19.1 mm diameter circle.

final_sentence: The Duodecar B12C base has 12 pins in a 19.1 mm diameter circle.