I have restored a Ford/Philco car tube radio from a 1930s Ford Coupe. The Car originally had a 6-volt system, but has had a type of battery installed in it that apparently changes to 12v to use an aftermarket 12v starter and then reverts to 6-volt afterward. I didn't know that when I got the radio and I am not familiar with how those systems work. Now I'm concerned that he'll crank the car and blow the filaments in all of the tubes by hitting them all with 12v. Could of course be sure it's turned off while cranking, but accidents are almost certainly going to occur eventually. Do those fancy batteries supply 12v to the entire car during startup, or just the starter? The car is in a different state or I'd just go check it myself. I guess what I'm asking is if there is a "proper" method of handling this type of situation. I thought about maybe getting a 6v SLA or lithium battery pack just for the radio but I'm wondering if the alternator would be an issue since the car is wired for positive ground. Don't want it trying to charge the battery pack. Anybody dealt with this?
Two 6V batteries in series ? (with appropriate circuitry to do the switching at crank time)
If it is that , just wire your radio to the one battery.
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I doubt the rest of the car is fed with a switchable supply - I would think it's isolated (pardon the pun) to the starter (and I would think it's a 12v alternator generator), what about the lights for instance... bright in normal operation and blowing when cranking ?.....
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You raise a good point about the switching battery. Just makes me paranoid. I don't want him to crank it and instantly pop every one of the tubes. I seem to remember the battery having only two terminals, but I wasn't giving it a very detailed look. I unfortunately don't currently have any pictures of the car. I didn't do a "Mr carlson's lab" complete restore of the radio. Basic cleaning, recap, alignment and lubed/cleaned the preset mechanism (which is still rusty and unreliable.) Re-printed the preset dial and replaced grille cloth. Put on a thick coat of VHT black wrinkle paint to protect the chassis from more rust. Original field coil speaker was trashed, so I unfortunately had to replace it. I added an input so he can listen to 30s-40s music and whatnot. Tried to keep it as stock as possible so that someone can return it to factory config in the future if they wish. The car's engine has been rebuilt and some of the wiring has been redone. The rest of the car is in decent but unrestored shape. It's a long-term project. Luckily it was garage-kept for the last several decades. Otherwise, I'm pretty sure the radio (and everything else) would have been destroyed by the weather.
Some of these systems have a relay connected to the starter switch that series connects the 6 v batteries for starting, then parallel connects them for charging lighting running. I have one of those relays I bought for my 1954 International bus.
Depends on how the car is wired. By fifties the ignition switch had a separate acc terminal that was not connected during starting. A 30's car could have had a pedal to make the starter contact. Lots of variation in replacing that. You could put a regulator in the radio to drop 12 v to 6 v, but it would require a pass transistor and a heat sink to run the 3 to 5 amps of a tube radio.
Depends on how the car is wired. By fifties the ignition switch had a separate acc terminal that was not connected during starting. A 30's car could have had a pedal to make the starter contact. Lots of variation in replacing that. You could put a regulator in the radio to drop 12 v to 6 v, but it would require a pass transistor and a heat sink to run the 3 to 5 amps of a tube radio.
Seems like a magic battery .....
Somehow I think this car's electrics don't revert to 6v after starting, however anything's possible (i.e. my original suggestion of two 6V batteries)
So I'm guessing the car has just been converted to 12v operation as detailed in these two articles:
6 Volt Car To 12 Volts
Converting from 6 to 12 volts
However your friends car conversion could be anything, you need to obviously specifically ask what's been done, then you can work around your radio connection without problems knowing what the precise setup is.
Far more vulnerable: all the LIGHTS in the car. 6V incandescents at 12V won't last a minute. 6V tubes @ 12V, many minutes.
And most car-radio tubes are CHEAP. 6V car lamps have become harder to source. Especially certain sealed-beam.
IIRC, the ACC (cigar lighter, radio) circuit was cut-out when in Crank so all power went to the cranker. However some cars are funny and any car that old has unknown repairs and bodges.
IMHO a good 6V car WILL crank excellently on a proper 6V battery. A 1930s Ford will have bad switches and poor connections, but the battery and crank motor work splendidly. (We had a 1940 Plymouth here for a while, a slightly better car, and once we went over the connections it was eager and always-start.)
And most car-radio tubes are CHEAP. 6V car lamps have become harder to source. Especially certain sealed-beam.
IIRC, the ACC (cigar lighter, radio) circuit was cut-out when in Crank so all power went to the cranker. However some cars are funny and any car that old has unknown repairs and bodges.
IMHO a good 6V car WILL crank excellently on a proper 6V battery. A 1930s Ford will have bad switches and poor connections, but the battery and crank motor work splendidly. (We had a 1940 Plymouth here for a while, a slightly better car
, and once we went over the connections it was eager and always-start.)
There are wiring diagrams online. Take them with a heap of salt. Ford didn't always do what they documented. 80 years of lazy and dumb mechanics. And the present owner has already done some mod.
What we said about an ACC circuit was not true then. The Cigar Lighter is the classic ACC load to be dumped when parked or cranking; but that cigar was more important than the battery charge so the 1940 has it right off the battery (not even a fuse). The starter switch just switches the starter relay/solenoid, no cut-off of unessential loads. The radio might be here, or after the ignition/instruments switch so it would default off when the car was parked.
I knew this and forgot. My 1949 Willys (but assembled in 1961) had these features.
What we said about an ACC circuit was not true then. The Cigar Lighter is the classic ACC load to be dumped when parked or cranking; but that cigar was more important than the battery charge so the 1940 has it right off the battery (not even a fuse). The starter switch just switches the starter relay/solenoid, no cut-off of unessential loads. The radio might be here, or after the ignition/instruments switch so it would default off when the car was parked.
I knew this and forgot. My 1949 Willys (but assembled in 1961) had these features.
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My first car was a 1949 Plymouth, probably with the same 218 cubic inch flathead as yours (my friends 42 Plymouth was the same). It was 6 volt positive ground. The factory AM radio was built by Motorola and had a pair of 6V6's for outputs. I wired my mono Panasonic cassette player through it's amp.
When I got tired of listening to the stock stuff I simply swapped the battery cables and made my car negative ground. No ill effects were seen from this change. At the time (1969) 6 volt VW Beetles were common enough that you could get a 6 volt to 12 volt step up box at a stereo store. They only worked with a negative ground system.
After blowing up two or three of these converters I did the unthinkable, I dropped in a 12 volt battery. As stated all the light bulbs lasted a second or less, so I put in 12 volt bulbs. The gas gauge stayed on full all the time, but the old generator would not charge the battery even with 12 volts on it's field coil, which fried it.
So the next step was to mount an alternator out of a 1965 Pontiac, and wire it to a two terminal voltage regulator from a 1965 Dodge Dart. That setup worked great and I was still driving that Plymouth until the early 90's. I did make a crude voltage regulator for the gas gauge with a transistor and a zener diode. Every few years I would break a Bendix gear on that 6 volt starter, so I got a rebuilder to rewind it for 12 volts. It lived on forever.
The 30's Ford coupes were popular with the hot rod crowd and this one may or may not have the original engine and electrics. I remember a battery back in the 70's that had three terminals. It was made for engine swaps in older cars. It charged and started on 12 volts, but had a tap at 6 volts for the rest of the car. I haven't seen one since the 70's and they weren't cheap then. Google does not find anything now.
The simplest thing here would be to ask the owner to get the numbers off several of the light bulbs in the car, then look them up and see what voltage they take. See if the owner could measure the voltage at anything inside the car with a cheap Harbor Freight digital meter. I know that 1940's cars had the same cigarette lighter socket seen in modern cars, but I don't know about anything from the 1930's. If it has the same socket, get one of the plug in voltmeters from Amazon and send it to the owner.
When I got tired of listening to the stock stuff I simply swapped the battery cables and made my car negative ground. No ill effects were seen from this change. At the time (1969) 6 volt VW Beetles were common enough that you could get a 6 volt to 12 volt step up box at a stereo store. They only worked with a negative ground system.
After blowing up two or three of these converters I did the unthinkable, I dropped in a 12 volt battery. As stated all the light bulbs lasted a second or less, so I put in 12 volt bulbs. The gas gauge stayed on full all the time, but the old generator would not charge the battery even with 12 volts on it's field coil, which fried it.
So the next step was to mount an alternator out of a 1965 Pontiac, and wire it to a two terminal voltage regulator from a 1965 Dodge Dart. That setup worked great and I was still driving that Plymouth until the early 90's. I did make a crude voltage regulator for the gas gauge with a transistor and a zener diode. Every few years I would break a Bendix gear on that 6 volt starter, so I got a rebuilder to rewind it for 12 volts. It lived on forever.
The 30's Ford coupes were popular with the hot rod crowd and this one may or may not have the original engine and electrics. I remember a battery back in the 70's that had three terminals. It was made for engine swaps in older cars. It charged and started on 12 volts, but had a tap at 6 volts for the rest of the car. I haven't seen one since the 70's and they weren't cheap then. Google does not find anything now.
The simplest thing here would be to ask the owner to get the numbers off several of the light bulbs in the car, then look them up and see what voltage they take. See if the owner could measure the voltage at anything inside the car with a cheap Harbor Freight digital meter. I know that 1940's cars had the same cigarette lighter socket seen in modern cars, but I don't know about anything from the 1930's. If it has the same socket, get one of the plug in voltmeters from Amazon and send it to the owner.
Thanks for the replies, guys. I'm just going to have to go back down there at some point and do some research. The car belongs to my uncle. My late grandfather bought it when he was younger and its been in the family since. My uncle has had one of his friends o the work so he's not really familiar with the technical bits. He's the one that told me "i had to get some kind of really expensive battery that switches between 12v and 6v for the starter" but he's not really all that familiar with what's going on. I may just make sure it's putting out 6v and run a dedicated (fused) rail with new wires to make sure everything is kosher. I still can't believe they used fuses so sparingly back then. Point to point wiring has many many potential short circuit opportunities but no fuse?!? Whaaaaaaaa??? That radio didn't originally have a fuse either. And I don't know much of anything about cars, vintage ones especially so. Thanks again guys. You've given me the confidence to take a shot at it.
That radio didn't originally have a fuse either. And I don't know much of anything about cars, vintage ones especially so. Thanks again guys. You've given me the confidence to take a shot at it.Many of model A fords 1928 to 1931 were coverted to 12v batteries and late model one wire 12v alternators. When the was done, all light bulbs had to be changed to 12v bulbs. The model A original starter was not changed and it simply spun fast with 12v applied. I was in a model A club and there was at least 15+ cars converted this way. Models A fords did not use a electric gas gauge or other instruments so voltage change was no issue. I would check the car to see exactly what battery was in it. If it is 12v lead acid battery, you will have to include an appropriate voltage dropping device to run the original restored 6v radio. I am surprised this radio is claimed to be an original as I have never seen a radio in a model A ford except aftermarket. Maybe it is a 3rd. party variant. Good luck Mickeystan
you just have to make a small circuit with a normally closed relay connected to the + wire of the starter solenoid.
when you activate the key, the relay opens, cuts the power supply to the car radio and as soon as the key returns to the normal position, the relay closes and powers the car radio.
it's a dream of mine to find one of these tube car radios just to put one in my workshop but in france, we haven't found one for years
when you activate the key, the relay opens, cuts the power supply to the car radio and as soon as the key returns to the normal position, the relay closes and powers the car radio.
it's a dream of mine to find one of these tube car radios just to put one in my workshop but in france, we haven't found one for years
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A radio from the 30's probably doesn't care about polarity. The original radio in my 1949 Plymouth had no polarity sensitive components on the primary side of the power transformer. It seemed to work fine both ways.
The old 6 volt car radios consumed considerable power. Mine drew far more than the 3 amps mentioned, but it was a big unit that had a pair of 6V6's for outputs. I don't know just how much it drew, but it made my 1960's vintage DIY power supply groan on start up. My VTVM didn't measure amps.
The DIY power supply built by a 14 year old kid in the 60's used a big Lionel train transformer, some diodes out of a car alternator, and several of the biggest caps I could find all wired together. It could light up lots of tubes at the same time without complaint or power my solid state experiments of the day which involved those big round germanium transistors off of the back of 60's car radios.
The old 6 volt car radios consumed considerable power. Mine drew far more than the 3 amps mentioned, but it was a big unit that had a pair of 6V6's for outputs. I don't know just how much it drew, but it made my 1960's vintage DIY power supply groan on start up. My VTVM didn't measure amps.
The DIY power supply built by a 14 year old kid in the 60's used a big Lionel train transformer, some diodes out of a car alternator, and several of the biggest caps I could find all wired together. It could light up lots of tubes at the same time without complaint or power my solid state experiments of the day which involved those big round germanium transistors off of the back of 60's car radios.
If I remember correctly, this one draws about 3.5 amps without the field coil. It was north of 5 amps with it connected, but not by a lot. I have a cheap bench power supply rated to 5-amps, and it ran it. It was NOT happy about it though. This radio only has SE output. Not a 6V6 though. It's one of the older tube types. UY base? 5-pins I think.
It appears to be a factory unit. The dash has a cutout for the head unit with slots for the speaker and knobs. The main chassis bolts on under the steering column. The chassis also has "Ford" embossed onto it.
It appears to be a factory unit. The dash has a cutout for the head unit with slots for the speaker and knobs. The main chassis bolts on under the steering column. The chassis also has "Ford" embossed onto it.
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That makes sense. Without the field coil connected you have no B+ current, only the tube heaters and the idle current of the vibrator and transformer.
The vibrator power supplies were not exactly high efficiency. I assume that this radio uses octal tubes and a 6 volt rectifier tube? I don't think the 0Z4 existed in the 30's, and loctals didn't show up until the 40's?
The vibrator power supplies were not exactly high efficiency. I assume that this radio uses octal tubes and a 6 volt rectifier tube? I don't think the 0Z4 existed in the 30's, and loctals didn't show up until the 40's?