If I think back to the moment when I tried the radio in my parents’ new car - may have been a 1961 Oldsmobile - the first car transistor radio I tried - it was probably the first time in my life I was crestfallen by the “new” falling so short of the quality of the “old” technology. I was an avid BCB DXer - listening to distant stations on the AM broadcast band - and the new transistor car radios were shockingly deficient.
@shanonia. The radio in the 1947 DeSoto had 8 tubes. I think it had more RF amplification than the transistor AM radios that came along in the 1960s
At any rate, nothing could beat that DeSoto coupe on s date, listening to Randy’s Record Shop on WLAC out of Nashville, TN, with your chickie snuggled up next to you on the wonderful bench seat and the tip-toe shift fluid drive so you didn’t have to shift gears. Today’s young people don’t know what they are missing with the bucket seats instead of a bench seat and WLAC doing talk radio instead of Randy’s Record Shop.
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The ‘classic’ tube radio had 5 tubes whose filament voltage requirements added up to 121 (1 took 50, 1 35, 3 12 - the ‘All American Five’ (look it up in Wikipedia)) earlier than that. The filaments were all hooked in series so they could run off house current. The exigencies of automobile power supplies and people’s willingness to pay luxury prices for car radio could have funded other architectures for them, but it was the standard for home radio. There were 6-volt filament tubes back then; you only needed to lower the resistance to get enough heat for the filament.
The big savings of the higher frequency were in the transformer, inductors, and capacitors, which shrank in proportion to the increase in frequency.
Filaments are just heaters: they don’t care whether they’re powered with AC or DC. Using AC injects that frequency into the circuit, which could be a problem, but if you’re selling cheap you can power them with AC.
@RandomTroll. I remember that tube lineup well. The rectifier tube was a 35Z5, the output tube was a 50L6, there was a 12AA7, a 12SK7 and a 12SQ7. The numbers in front of the tubes indicated the filament voltage. These numbers added up, as you indicated, to 121 volts, about the 120 volts of the AC power in the house. The rectified and filtered voltage was fed to the plates of the tubes and was about 120 volts DC. This eliminated the need for a transformer to boost the voltage for the plates of the tubes. The filament power was the A voltager and the plate power was the B voltage.
On the vacuum tubes in the Rambler radio, the filament voltage was probably two or three volts while the plate voltage was 12 volts. The filaments of these tubes may have been connected in series.
The transistors really simplified things. Instead of a cathode heated by the filaments, a plate and a grid to control the flow of electrons between the cathode and the plate, the transistor has an emitter where the electron flow starts which flows to the collector and the rate of flow is controlled by the base. I was amazed that the transistor poetable radios that came out in the late 1950s were powered by one 9 volt battery as opposed to a tube type portable radio that required a 6 volt A battery and a 90 volt B battery. Obviously, the transistor radios in cars could operate very well on the 12 volt car battery and didn’t need vibrators, transformers or rectifiers as the old tube car radios had to have.
Now that you bring up abbreviations, I remember ‘RH’ for radio heater.
Our family’s 1941 Studebaker Land Cruiser Commander had a very nice sounding factory radio.
Space charge tubes. Limited performance and mechanically delicate.
@circuitsmith. Thank you for the link to space charged tubes. I had wondered about how these tubes functioned for years, but never took the time to do the research. My interest in electronics has waned over the years, so it was great to have the link.
My 53 Buick had a great radio and an antenna the sprouted from the roof right over the center of the windshield, with a knob inside that you could rotate to get the antenna aligned best with the radio signal. The radio was huge, and when I turned it on with the engine idling the lights dimmed. And the dash got pretty warm around the radio, so it was sort of a heater. I drove it from Connecticut to Colorado once and listened to KOMA from Oklahoma City from about Columbus Ohio area to the first big pass in Colorado (Rabbit Ears?)
The car was not so great.
Not that it adds anything but when you mentioned a 53 Buick, it just dawned on me about the picture I saw at the Acura dealer today. I had to get transmission, differential, etc. fluid changed so I had some wait time. On the wall I noticed they had an old picture of their dealership with about 10 Buicks (somewhere between 53 and 56 models) proudly parked outside. Great picture but it never registered with me until now that it must have used to be a Buick dealer back in the 50’s and then turned into an Acura dealer sometime. Same name, just different cars.