This document is intended to showcase a small cross section of tubes used in early radio equipment.

1934_Thermionic_Tube_Chart_s.jpg A  lineage for thermionic tubes 1883 to 1934. Click on thumbnail to enlarge. ( Edited by Kent Leech)

Early radios used 00, . 01A and also Cunningham 300 series tubes. Data for these types is provided here.
00_and_01_tubes_s.jpg Click on thumbnail to enlarge. This page for the 00 and  01 tubes is from the 1937 RCA  tube manual (Provided by Lewis Bodkin)


cunningham_30x series_s.jpg The letter "C" and the three hundred series was for the Cunningham brand.  Click on thumbnail to enlarge. From the 1921 Duck catalog.

Both 200 and 300 as a series number were later dropped.. The Cunnigham 301  was the same as a CGE 201 (Provided by Lewis Bodkin)

Marconi 'Q'  valve  (See credit #2)

Introduced in 1916, this triode had widely positioned leads to minimize inter-electrode capacitance. It was a high impedance tube, used primarily as a detector. Like all early Marconi valves, it was made originally by Edison Swan but after 1919 by MOV. 

Filament: 6 VDC @ 0.4 amps
Anode voltage: 150 to 200 volts as an amplifier; 25 to 30 volts as a detector. 
Anode resistance:  150,000 ohms.

Marconi 'V24' Tube.  (See credit #2) 

This tube, a directly heated triode, was a development of the 'R' type aimed at improving high frequency performance. The V24 was introduced in 1916 by Marconi UK and was used as an RF amplifier. To reduce parasitic capacitances  the leads of the valve were separated as much as possible. For replacement purposes


Filament  -  5 volts at 0.75  Amps
Anode voltage: 20 to 60 volts (24 volts was typical  hence the name V24).
Amplification factor:  6
Anode resistance: 15,000 to 20,000 ohms

Although MWTC used Q valves and V 24 valves in their receivers and amplifiers before March 1922, it is unlikely that any of these valves were made in Canada.  For replacement purposes, the V24 valves were still being made as late as 1937. 

A more detailed view of the V24 tube. So far, there is no evidence to show that any of these tubes were manufactured in Canada earlier than the latter part of 1921 according to Radio Trade Builder magazine ,December 1934. (Photo by Lewis Bodlin)
This NOS (New Old Stock) V24 valve comes in its original box (Via E-bay, UK) 
This is an adapter for socketless tubes such as the V24. (Image provided by Lewis Bodkin) 
This adapter for socketless tubes would have been used in radios that employed the breadboard technique of fabrication. Image provided by Lewis Bodkin) 
This adapter facilitates the mounting of a socketless tube in a horizontal position. (Image provided by Lewis Bodkin) 

Type: UV-201 receiving triode. 
Filament - Pure tungsten. 5 volts @ 1 amp. 
Plate Voltage 135 VDC max
Amplification factor: 8 
Vintage: 1922 
Comment: The UV prefix meant  Universal Valve base; one having four short pins.  Introduced in 1922, the UV201A  uses a thoriated tungsten filament which only draws 250 ma. (Photo by Louis Bodkin)

Manufacturing of the UV 201A began at the earliest in October 1922. By August 1923 it  it became Marconi's most popular selling tube. 

In the  UV designation, U signified that it was an apparatus unit and V meant 
that it was a vacuum tube. This system of significant tube coding broke down rather soon. In the first RCA catalogue, dated September 1921, there was offered for sale,  the UV712 Audio Frequency Intervalve Transformer ! 

In 1934,  RCA , GE, and CGE  renumbered tubes that they had made throughout the 1920s.  The 200 series became two digit numbers.  So 201-A became 01-A. Number 199 became 99. The  201 tube was no longer being made at that time.  As well, the Cunnigham  brand tubes made by GE in USA were no longer being made.

1930s or LATER

Type 12A triode (Ebay photo)

1C21 Thryatron 

1625 beam power tetrode 
832A transmitting tetrode
6SN7 dual triode
12AV6  Double diode and triode
12SA7 - Single ended series example
All photos in this table by Pierre Lewis

6L5G Power Triode Amplifier 
12BZ7 high-Mu twin triode 
6397- Power Amplifier Pentode 
6AF6 miniature, octal, magic eye tube.
All photos in this table via E-bay

This example of a 12SC7 tube, was built under contract and was common to all the Canadian Forces. The 12SC7 is a hi-Mu twin triode. (E-bay photo)
This 5961 tube, packaged generically,  was built specifically for the RCN in February  1959. (Photo by Tom Brent) 

This 6204 tube with a blue finish was never registered, but it is a 6.3 volt, half wave rectifier that is equivalent to one half of a type 6X5. 

The 5961 tube, also painted blue is described as as "Canadian reliable 6SA7".

Marconi made a 6006 tube whose finish was red. This is identified as a "ruggedized remote cutoff pentode (Canadian) version of the 6SG7". 

The 5961 and 6006 tubes mentioned above were referenced from : MIL-HDBK-213, "Electron Tubes Interchangeability Directory" published by the United States Department of Defense and dated November 02, 1959

A more contemporary tube carton. (E-bay photo)
The topmost tube carton is of interest because it was made for Canadian Marconi in Japan. (Image via Kijiji,ca) 

Front cover of the RVC/CMC Tube Manual, 1949 edition. 
Table of contents for this 75 page manual.
Rear cover of RVC Tube Manual. It has been accidentally stained. 
All images in this table via Ebay. Download image to enlarge. 

Canadian Marconi tube manual from 1952. (Image via Kijiji)

A 223 page Canadian Marconi tube manual whose vintage is not knoen at this time.  Included are the physical and electrical characteristics of all popular television picture tubes. It looks like the price was 75 cernts 

Ink blotters, such as these, were used for advertising purposes when the vacuum tube was king along with pen and ink. (E-bay photo)

tube_price_list_1939.jpg This is page 1 of a tube price list for July 1939, Click on image to enlarge,  (Image via E-bay) 
How did RVC come to use the Radiotron trademark?

RCA was formed in 1920  as an operating company for the purpose of providing ship-to-shore and transoceanic communication. It had no manufacturing facilities until the formation of a subsidiary company, namely  RCA Radiotron .  The earliest listing of "Radiotron" at the patent and trademark office (USPTO) is April 28. 1921 for application. It was issued in 1922, however its first use in commerce is 1920. The trademark was registered to the Radio Corporation of America. who in turn licensed tts use to Canadian  Marconi, Amalgamated Wireless of Australia, Westinghouse  and other companies who were licensed by RCA to use its tube patents.There is no indication of any earlier registration of the trademark by anyone other than RCA.

Contributors and Credits:

1) Pierre Lewis <leware(at)>
2) V24 and 'Q' photos by Ben <benam(at)>
3) V24 Description
7) Tom Brent <navyradiocom(at)>
8) “The Early Development of Radio in Canada 1901-1930 by Robert Murray”.page 31
 for RVC9) Jim Cross <jimcross(at)>
10)  Lewis Bodkin  <05bodkin555(at)gmail,com>
11) V24 and Q tube specs: Scientific Experimenter March 1921
12) The Early Days of Broadcasting 1920-1930 Page 309
13)  Richard Knoppow  WB6KBL  <1oldlens1(at)>

Sept 15/21

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