6 volt Radio?
 

Has anyone ever seen a radio that runs off of a six volt battery? A friend bought one and wondered if there was a way to convert it to 110? If anyone knows if this is possible I would like to know. I will try to get more info, I haven't seen the radio yet.

Thanks

Tom

I've rebuilt 6V car radios. You can build a power supply for it.

Old farm radios were the more common battery types, before standardized electricity was getting out to rural areas. Plus, 6 volt car/truck batteries used to be the norm before the mid-late fifties..

They, have what is known as a "vibrator power supply". think of it as a Switching power supply, but with a vibrating relay in place of the switching transistors and oscillator. This is EXACTLY how they work. The 6 volts( or in a few cases--2 volts, I have a couple of old GE "lunch box" radios, model #250 IIRC, that use a single large 2 volt battery. That powers the filaments of the tubes and the vibrator supply--it then produces over 100 volts that is then used for the B+ supply. In a car radio the 6 or 12 volts does the same thing--the car voltage powers the filaments...the vibrator supply raises this to over 200 volts usually--for the tubes B+. The output of the vibrator transformer is then rectified by a tube OR another set of contacts on the vibrator itself, known as a "synchronous" vibrator.

To power by 120 volts, One needs to either simply supply the 6 or 12 volts to the radio from a power supply..( the easiest way...) OR replace the vibrator tranny with a 120 volt unit. I have seen this done before.

Somewhere, I've got a mid '30's 6V Silvertone radio. And, there were also 32 volt radios.

There are a number of ways to convert 6 volt radios to 110. In the old days it was routine for an Elmer to re-engineer the power supply and audio output stages from scratch to use AC set tubes in a re-purposed farm set. I prefer to keep a radio as original as possible. Last year I converted an interesting Setchell Carlson radio to AC power and did so maintaining its unique tube complement: 6D8, 6S7, 6T7, 19, 19, 19.

http://i163.photobucket.com/albums/t...X/setchell.jpg

As you can see, one of the 19s is used as a rectifier. The other two needed pure DC for their filaments, so the easiest solution in this set's case was to keep all filaments DC.

The vibrator was eliminated and a couple of connections were moved, otherwise the original circuit was left entirely intact and the mod is at least theoretically reversible.

There were also 12V tube car radios that didn't need a vibrator. They used tubes designed to use the space charge effect. I don't know if any farm radios were designed to use them, but you can easily build a radio that works at 6 volts.

There is some information at Space Charge Tubes

John

I've seen a few of those auto radios that used 12V tubes. The ones I saw used a transistorized audio output stage and tubes for the rest of the set. I think these were used from the late '50's up until the early '60's, when SS took over.

I think they all had to have a transistorized output stage in order to get enough volume. I forgot about that.

John

I have a Stewart-Warner that took a different approach - it has a big honkin' external power supply that looks vaguely like a military ammo can (but it's not, it has S-W markings on the top).

I have a Montgomery Ward Airline and a Zenith set that will play on 6 volts DC or 120 volt AC. Both have a switch on the back to change the power input. I've also got an Airline Movie dial 6 volt table radio and a Zenith tombstone. The 6 volt sets are not as common as the A-B pack farm sets but they show up fairly frequently in rural areas.

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One problem with the 32-volt farm radios was that they had the same kind of plug at the end of the power cable as today's 110-volt appliances. This was not really a problem in the days of 32-volt radios (the late 1920s-'30s), however, as the power outlets in farm houses were the same type; the power to these outlets came from wind-powered generators (windmills) that also charged batteries, which supplied power when the wind died down at night or on calm days. The problem is that if someone has one of these 32-volt radios today, if the person did not know the radio was wired for 32 volts, he or she could plug the power cable into a 110-volt AC outlet......and ruin the radio in the blink of an eye, as soon as the set was turned on. I've never seen one of these radios burn up from overvoltage, but I bet it would make a display of sparks and exploding parts :yikes: one wouldn't soon forget.