1945-1959 Post War Tube Radios

Page 3

1950's: The Rise of the Portable Radio 

The invention of the transistor push the size of the portable radio to the point where people wanted to hide the radio until they needed.

Directed by Norman Krim, Raytheon developed subminiature tubes during WW2 and carried that technology into portable equipment. He made a deal with the head of Raytheon that they could develop a pocket radio that was marketable or he'd quit.  Raytheon took over  Belmont Radio to make t he first pocket tube radio the Belmont Boulevard in the late 1940's. It didn't sell well but the technology found its way into hearing aids where size was important, but battery life was still a problem. Krim kept his job at Raytheon and moved the company to a successful business, making transistors. The transistor solved the battery life problem, but they were expensive and difficult to make during the 1950's. Although Bell Labs invented the transistor, companies like Raytheon, Texas Instruments,GE, RCA, Philco and others capitalized on it and took it from there. 1950's gave rise to the Hybrid radio and hearing aid where a mix of tubes and transistors were used. Hybrids were mostly subminiature tubes  used with one or two transistors added in to save power, cut size and sell the item as the latest technology.
 Compare Raytheon Smallest Tubes with Early Transistors

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       COMPACT                                                  TRYING TO BE DIFFERENT....                             TRADITIONAL

Motorola 45P1 (1955)" PIXIE", Motorola (Galvin) Chicago IL.  Camera style. Uses subminiature (Peanut) tubes, 1V6, 1AH4, 1AJ5 and 1AG4.
Of all the compact sets in the collection, this model is the easiest to replace batteries and replace tubes.. Open the back door and it's all in front of you!
Westinghouse H-491P4 (Peter Pan) Westinghouse Electric, Metuchen NJ: 1954-55?? Subminiature Tubes. Unique carrying handle that doubles up as a stand. Uses 4 subminiature (Peanut) tubes (1V6 Triode-Pentode, 1AH4, 1AJ5 and 1AG4 Beam Pwr). 
ABOVE: 3 1/2" speaker and access to the tubes. Notice how large the tuning capacitor is. BELOW: Most components replaced by two ceramic couplates (thick film network). This is the first time I have ever seen two couplates used on an AM set. 
ABOVE: Elaborate battery removal and storage! Requires 45 V mini B battery and 1.5 V C size A Battery. BELOW: Backside, to change tube remove the 4 screws on the white cover  and pull cover off.
Westinghouse H-564P4, Westinghouse Electric, Metuchen NJ:  Slightly larger than the H-491P4 and uses conventional miniature tubes (1R5, 1U4, 1U5 and 3V4)

Made in Japan

The post WW2 period in Japan was a rebuilding period. Early Japanese radios of this period was a mix bag of various technology, mostly of American designs simplified to reduce manufacturing costs. Result was a smaller product and simplified designs but mediocre to poor performance. Early Japanese products had the perception of cheap in all areas- making "you get what you pay for" a really good buying axiom.
Star-Lite SM-300 (circa 1955 and made in Japan). Imported by Star-Lite Electronics Corp, NY. Four tube battery portable purse size radio. About the same size as the Emerson 747 but uses standard miniature tubes 1R5, 1T4, 1S5 and 3S4.  A Battery is a 1.5 VDC D Cell and a 67.5 VDC compact B Battery,
ABOVE and BELOW:  Notice how compact the radio is. Compare the A Battery with the rest of the parts. Changing tubes require removing radio out of case and some disassembly such as the removal of antenna loopstick.
ABOVE: Wiring is very tight and crowded. Some of the resistor and capacitor values marked did not match the real value. However the value matches the schematic value. This tells me that some of the parts were rejects and recycled for other applications, I remove them and replace with correct part.
The Privat-Ear 5-DS-001 (1951)Uses  2- 2E31 Subminiature Tubes. Before Sony brought out the Walkman, this tube radio was one of many attempts for the real carry around private radio that could fit in a pocket. Pull the antenna all the way up turns on the radio.
Listen to the Privat-Ear 5-DS-001 BELOW
Privatv Ear 5-DS-001.wmv
Inside the Privat-Ear
Emerson 747 (1953) Emerson Radio, New York  (Subminiature Tubes) Had great popularity with women because it could fit in a handbag). It was a trendsetter. Uses 1V6, 1AD4, 1AH4, and 1AG4.
ABOVE: Component seem to be mounted on a printed circuit board, which is really a phenolic board with holes drilled into it for mounting components and standoffs to handwire underneath as shown BELOW: The wiring is tight.
To change tubes, removal of the front panel is required.
Emerson 838 (1955) Emerson Radio, New YorkEmerson took the 747 and made it into a hybrid set featuring two audio output transistor ninstaed of the 1AG5 sumniniature tube. The other tubes,1V6, 1HA4 and 1AD4 remained. They called it the transistor radio. The two audio transistors were made by Texas Instruments. The radio used the same B battery as the 838, but the A battery was a special 4 volt mercury battery to power the tube filaments (now series connected) and transitor B+ supply.
ABOVE: The three tubes connected like the model 747 except the tube filament are now connected in series. BELOW: underneath the phenolic board shows the two output transistors on the right.
Like the model 747, access to tubes and transistors require removing the front panel.

Video, 

Relation between the compact Emerson 747 and the Transistor Emerson 838.
Emerson 747 and 838.mp4
Emerson 640 (1954):Emerson Radio and Television, New York.  Compact suitcase style. Battery only (67.5 V B-Battery and 1.5 V A-Battery. Tubes 1R5, 1T4, 1U5 and 3S4. Very nice portable radio that was made to fit in a large purse or travel luggage. 
ABOVE: Lifting the top lid turns on the radio and exposes the antenna. BELOW: Unlatching the bottom lid exposes the batteries and chassis. Notice that the IF-RF section is on the RIGHT and the detector and audio amplifier is on the LEFT.
1956-57 RCA 1-BX-79 (The Cruiser)  3-way portable using selenium rectifier and 1R5, 1U4, 1U5 and 3V4 battery tubes.
Top chassis of RCA 1-BX-79 showing tubes along with 7.5 Volt A and 90 Volt B battery placement.
Under chassis wiring. Look at the size of the electrolytic versus the other parts.
Front View showing rotating antenna and cute rotating red annular shade tuning indicator sync with the tuning knob.
RCA 2B405 (Below) 1952 model, showing front and inside with original batteries. Suggested price $29.95.
Airline (Montgomery Ward)94GCB-1064B Camera style radio, battery operated only. Uses 1.5 V D size "A" battery and 67.5 V "B" battery. 1R5, 1T4, 1S5 and 3S4 tubes used.
The lid is an on-off switch and antenna also.
ABOVE: Paper capacitors are small and rated at 100 WVDC. Resistors are 1/4 W IRC brand.BELOW: Tube access requires the batteries to be removed, but it is still difficult.
Tele-Tone 214 (1952)  Lunchbox style 3-way portable. Tele-tone New York, NYThrowback to late 1940s technology.5 Tube portable using 1R5, IU4, 1U5, 3S4 and 117Z3.
Still uses a tube rectifier (117Z3) for AC operation.
ABOVE: Teletone back open  and below the 117Z3 rectifier is the only tube with a noticeable glow. Also shown 
ABOVE: Tele-Tone 214 chassis removed from cabinet. The two slots on top of chassis, disable the tube rectifier for battery >>>>> operation. Inserting the plug prongs into the two slots on the chassis will flip a switch to disable AC operation.

Vintage A-B Battery Tester

Eveready Radio Battery Tester


Will test the following A (Filament) Batteries1.5, 3, 4.5, 6, 7.5, and 9 V
Will test the following B (B+ source) Batteries22.5, 45, 67.5 and 90 V
Will test Special Purpose Batteries15, 30 and 75 V

Zenith Transoceanic L600 Multiband (1954) 

Still the Standard for portables.
Started in 1941, this is the 5th generation and their best tube portable. With very slight upgrades this design continued until 1963 and was the last tube Transoceanic. Designed for shortwave listening, Zenith used bandspread tuning to easily tune in stations. Can run on AC or batteries. Uses 5 tubes, a ballast regulator tube and a selenium rectifier for instant on. 
Antenna, Front and back panels close up and radio looks like a suitcase.
Illuminating Dial for evening use. Only  tube Transoceanic to have this.
Retractable AC cord, Flip out charts and removable wavemagnet to improve reception.BELOW: Layout of top chassis. Has TRF front end and custom matched IF xfmrs for good sensitivity and selectivity.
ABOVE: Crowded chassis, Zenith started using molded paper capacitor and some ceramic disc capacitors. LEFT: Access to rear to change batteries, get the instruction book or connect an external antenna.
Features a retractable and lock down telecsope antenna and the tone control is based on Zenith's "Radiorgan" switch settings.
Band selection is based on wavelength. Actuation by pushing the desired button.

A Portable in a Class By Itself


Motorola 53LC2 (1953) 3-Way Portable Clock Radio, Mototola (Galvin) Chicago IL


A strange radio because it uses subminiature or peanut tubes in a cabinet that is big enough to use the standard size tubes. Also the batteries are huge. Features mechanical wound clock made by New Haven Clock ( a pocket watch was used). Has selenium rectifier for AC operation. What Motorola had in mind is a mystery.
Tubes use: 1V6, 1AJ5, 1AH4 peanut tubes and 3S4 miniature tube. The 3S4 power pentode puts out about .18 watt while the peanut power pentode 1AG5 (used in many compact radios of this period) puts out .035 watt.

<<LEFTBIG SIZE: The set is 9 1/2" wide and 8 1/2 inches high!







<<LEFTLook at the Inside- See all the space and the large batteries. Notice how small the tubes are.
The speaker was a large 5X8 speaker with an inverted cone saving space. However the speaker was bad so it was replaced with a 2X5 flat speaker used in flat panel television sets.

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