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From Vacuum Tube to Transistor Radios
The family lines shown below illustrate the transition from vacuum tubes to transistors and the manufacturer's marketing strategy to emphasize the model line distinction.
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RCA Globe Trotter (AKA Globetrotter) Standard Broadcast AM Portable Radios 1946-1972
RCA Globe Trotter (AKA Globetrotter) Standard Broadcast AM Portable Radios 1946-1972
In the late 1940's RCA introduced a portable AM radio that had long distance capability using a TRF front end tuning stage. With one exception all RCA Globe Trotters have slide rule tuning .
The First Globe Trotter-1946
This was the 66BX later BX6 and 8-BX-6 in the 1950s. Except for slight variations of the cabinet trim all are the same design. These are 3 way portables AC/DC and battery only). They represent the largest of all Globe Trotters at 13" wide and 10 1/2 inches high. Since that time until the end of the -Globe Trotter line, RCA continued to build the Globe Trotter with the TRF front end operation. This style was used for several years with basically the same chassis (RC-1040A), only the model number changed. A 117Z3 rectifier was used making this a 6 tube set, ( 2- 1T4, 1R5, 1S5, and 3V4) the most for a portable Globe Trotter. Later versions replaced the rectifier tube with a selenium rectifier, resulting in rapid start up. NOTE: The only portable Globe Trotter without the name Globe Trotter on the set but advertised as so.
RCA 66BX (AKA 8BX6 and BX6) lift the front cover reveals the dial and turns it on. When the lid is closed the radio turns off. Unfortunately the almost all aluminum case restricts the reception ability of this quality radio circuit. They offered an external loop for better reception.
66BX top chassis below. Notice the 3-section tuning capacitor on the left. RF-ANT-OSC sections. This is found in all Globe Trotters. The 1S5 detector and 1st audio tube is at the back right corner behind the 117Z3, requires removal of chassis from cabinet. .
Shown with battery installed. Uses a 90 V and 7 1/2 volt A-B Battery pack.
Most RCA Globe Trotters use a 4X6 speaker. Photo shows the gold tuning and volume control wheels.
RCA 7-BX-8L mid 1950's Tube Globe Trotter. major change from 66BX is the use of a rotatable antenna outside the case eliminates the need for an external loop for better reception, 4" square speaker, collapsible carrying handle and all plastic case except front trim. 3 way operation. RCA replaces vacuum tube rectifier with a solid state selenium rectifier for quick turn on. The set of tubes are the same as the 66BX without the 117Z3 rectifier.
Inside the 7-BX-8L. Notice the large AB battery
Other Vacuum Tube Globe Trotters
1953 2-BX-63
RCA 1-T-5J Transistor Globe Trotter (Mid 1950's). Probably the first transistor Globe Trotter. Notice the similarity to the 66BX, the first portable Globe Trotter. Lifting the cover exposes the tuning dial and turns on the radio. Unlike the first Globe Trotter, the use of the aluminum was only the front panel, so eception is very good with internal loop stick antenna. Uses batteries only.
Large 4 X 6 speaker. The size of the audio an IF transformers are typical mid 1950's solid state technology.
RCA 3-RG-81 Early 1960's Transistor Globe Trotter. Runs on batteries only. Made in USA. Has 8 Transistors.
Had to replace several electrolytics that had opened up over time. Used 4 X 6 speaker.
The circuit board component side is facing front. Most transistor Globetrotters are the reverse. Notice the 3 section tuning AM band capacitor, a Globetrotter distiction.
RCA RWG-135E (1968-69) Transistor Globe Trotter (made in Japan). AC/DC operation. Only one with a log scale and slider controls.Has tone control. 8 Transistor Radio. Like the RZG-133E below, later models did not have the Globe Trotter label on it.
Probably the smallest circuit board of the transistor Globetrotters. Notice the first time use of 3 section plastic tuning capacitor and epoxy encapsulated silicon transistors. 4 inch round speaker is used.
The best cord storage of the AC-Batt Globetrotters.
The Last Globe Trotter? 1969-70
RCA RZG-133E (made in Japan 1969-70) 8 transistor Globe Trotter AC-battery operation and has tone control. Good example of early 1970 lunchbox portables showing faux leather black case. Later production models had the Globe Trotter name deleted.
Unlike the RWG-135 which used a sturdy plastic case, this model case is all vinyl and paper construction. With some cabinet freshing up this model is very similar to the mid 1960s RLG-34.
RZG-133E Globe Trotter circuit board. All Globe Trotters from 1946-1976 have 3 section tuning capacitors- RF-ANT-OSC tuning sections and RF transformer..
Return to the three section metal construction tuning capacitor.
Other Transistor Globe Trotters
1958 1-BT-58 (all transistor but no TRF front end)mid 1960s RHG-30 (only one without slide rule dial)late 1960s RLG-34
Zenith Zenette Portable Radios 1948-1960
Zenith Zenette Portable Radios 1948-1960
A name that has been used since the 1930's. Usually refers to a compact unit that tauts Zenith quality but in a manageable size or versatility.
Zenith Zenette 4G800Z (1948) The original version in this style. During 1948 to 1949 Zenith made several production changes mainly in the power supply circuits and the change from the 3Q4 to the 3V4. This model came in ebony, maroon and white.
With Covered Closed. When you open the lid the radio turns on. The lid also serves as the antenna
Compact electronics in a 1940-1950s Zenette (before restoration)
Zenith Zenette G402 (1951) Introducing a Gray Color. Notice the changes in the LOGO.
Left: Transistor version (Royal 100- 1959) and the original Tube version (4G800Z- 1948)
1947 Tube Zenette versus 1959 Transistor Zenette
Compare with transistor version of the Zenette (1959)Royal 100
Zenith Transistor Royal 100 ZenetteCame in 5 Colors- Dark tan, green, yellow, off white and black
6 Transistor Radio operating on 3 AA cells.
Zenith Transistor Radio Family Lineages The Royal 50 and 500
Zenith Royal 50 Series 1960 to 1962
Zenith Royal 500 Series1956 to 1966
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