07-15-2026, 12:01 AM
Car radios were introduced only about 1929 or so and were loosely based on the battery powered radios of the time. See the Schematic for the 1930 Philco Transitone Model 3 here (along with the famous Model 20):
This was a TRF set that used 24A tetrode (Screen Grids) for 3 RF amps, a 71A connected as a diode for a detector 2 01As as Audio am stages and a 71A as an output tube with a whopping 0.7W for your listening pleasure in your super quiet Model T or Model A Ford. The heaters of the 24As were in series and there were dropping resistors for the 5V tubes. This set was powered from the car battery and 180V worth of B Battery blocks. Expensive to buy, expensive to run. They even had keys so the vehicle owner could regulate the use of the car radio, so they didn't have to run out to buy four 45V battery blocks or find that the car won't start. However, the radio DID have AVC. The antenna for the set was either mesh in the soft top of the car or a plate mounted below the running boards. Eventually Dynamotor, then vibrator power supplies were introduced to replace the B Batteries.
By about 1934, car radios had matured to circuits similar to home radios. Your Model 10 featured a very good circuit consisting of a 39/44 RF amp, 6A7 Pentagrid converter, a 39/44 IF amp, a 75 Detector /1st AF Amp / AVC and a 42 Pentode, having a rather good 2.5-4 Watt output, similar to a medium priced table or console radio for the home. THis radio was no slouch, it was a great performer, equal to the car radios of the 1950s. Note from the Nostalgia Air circuit diagram tof the Transitone 5 and 10 that the Transitone Model 5 offered a similar circuit but without the RF amp, with a more modest 41 output tube.
The electromagnetic dynamic speaker 's field coil was often powered by the car's 6V battery as opposed to being a higher resistance coil and used as a filter choke in the power supply.
When I was a kid, I used to find radios in cars at the town dump (At the time scrap metal prices were very low and they buried the cars). Since I did not have access to a car battery (Dad was not very happy if I opened the hood and ran them off the family Ford), I tried to find 6V models which I ran off the filament windings off an old TV power transformer. This was easy as I was 12 in 1967 and there were plenty of 1949- 1959 and earlier cars in the dump. I figured that since the purpose of a vibrator was to produce AC, well just running the whole thing off 6V AC was not a problem. Eventually, I found a transformer with 2 6V windings and put them in series to get 12V. Never found an AM-FM radio however, nor a transistor one. Plenty of "transistor powered" car radios. Vibrators were eliminated in 1959- 1962 cars by using "space charge" tubes that functioned on 12V for B+. The output stage of the radio was a transistor (usually a Delco 501). Schematic here:
One certainly could not power this with 12VACThis continued till about 1963-1964 when most cars migrated to transistors. Chrysler introduced the first Transistor car radio in 1955 for 1956 Chrysler and Imperial models. This option was $150, vs about $3,000 for a Chrysler. Ford introduced all transistor radios in the 1961 Lincoln and Thunderbird cars.
Hope this helps.
This was a TRF set that used 24A tetrode (Screen Grids) for 3 RF amps, a 71A connected as a diode for a detector 2 01As as Audio am stages and a 71A as an output tube with a whopping 0.7W for your listening pleasure in your super quiet Model T or Model A Ford. The heaters of the 24As were in series and there were dropping resistors for the 5V tubes. This set was powered from the car battery and 180V worth of B Battery blocks. Expensive to buy, expensive to run. They even had keys so the vehicle owner could regulate the use of the car radio, so they didn't have to run out to buy four 45V battery blocks or find that the car won't start. However, the radio DID have AVC. The antenna for the set was either mesh in the soft top of the car or a plate mounted below the running boards. Eventually Dynamotor, then vibrator power supplies were introduced to replace the B Batteries.
By about 1934, car radios had matured to circuits similar to home radios. Your Model 10 featured a very good circuit consisting of a 39/44 RF amp, 6A7 Pentagrid converter, a 39/44 IF amp, a 75 Detector /1st AF Amp / AVC and a 42 Pentode, having a rather good 2.5-4 Watt output, similar to a medium priced table or console radio for the home. THis radio was no slouch, it was a great performer, equal to the car radios of the 1950s. Note from the Nostalgia Air circuit diagram tof the Transitone 5 and 10 that the Transitone Model 5 offered a similar circuit but without the RF amp, with a more modest 41 output tube.
The electromagnetic dynamic speaker 's field coil was often powered by the car's 6V battery as opposed to being a higher resistance coil and used as a filter choke in the power supply.
When I was a kid, I used to find radios in cars at the town dump (At the time scrap metal prices were very low and they buried the cars). Since I did not have access to a car battery (Dad was not very happy if I opened the hood and ran them off the family Ford), I tried to find 6V models which I ran off the filament windings off an old TV power transformer. This was easy as I was 12 in 1967 and there were plenty of 1949- 1959 and earlier cars in the dump. I figured that since the purpose of a vibrator was to produce AC, well just running the whole thing off 6V AC was not a problem. Eventually, I found a transformer with 2 6V windings and put them in series to get 12V. Never found an AM-FM radio however, nor a transistor one. Plenty of "transistor powered" car radios. Vibrators were eliminated in 1959- 1962 cars by using "space charge" tubes that functioned on 12V for B+. The output stage of the radio was a transistor (usually a Delco 501). Schematic here:
One certainly could not power this with 12VACThis continued till about 1963-1964 when most cars migrated to transistors. Chrysler introduced the first Transistor car radio in 1955 for 1956 Chrysler and Imperial models. This option was $150, vs about $3,000 for a Chrysler. Ford introduced all transistor radios in the 1961 Lincoln and Thunderbird cars.
Hope this helps.
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Best Regards,
MrFixr55
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