i just bought a 6volt battert U-51 G.E. radio., it says its a 6 volt radio, is there a easy diagram of how to convert it to AC. if theres a diagram around, please email to me., southerncontry@yahoo.com

Hi Paul

Not reasonable to convert this radio to AC. It uses DC filament type tubes and a vibrator supply for high voltage.

http://www.nostalgiaair.org/PagesByModel/269/M0008269.pdf

Best to buy or build a 6 volt power supply. You could start start with a battery charger and add filtering & regulation.

Norm

:i just bought a 6volt battert U-51 G.E. radio., it says its a 6 volt radio, is there a easy diagram of how to convert it to AC. if theres a diagram around, please email to me., southerncontry@yahoo.com

I've encountered a couple of farm radios that had been converted to AC, but none that used DC tube heaters, as pointed out by Norm.

The conversions I've seen were hatchet jobs which, to my eye, wrecked the sets. By the time they ripped out the vibrator ckt, added a transformer and rectifier, it was a mess.

Battery chargers (ones that can be switched from 12 to 6 volts) have worked well for me with radios that contain all AC tubes. As Norm said, your radio has some filamentary tubes, which need pure DC, and are picky/delicate with too much current. Be sure to filter the charger well, say with multiple 3500 MFD electrolytics in parallel. You may want to place a very low resistance resistor in series with the radio to bring the voltage right to 6.0 volts, or at least no more than 6.4 volts. Radios with AC 6.3 volt tubes can handle up to 7.4 volts, but filamentary tubes are a bit more delicate. A simple coil of 20 to 22 gauge wire may be all that is needed to reduce current appropriately (you determine how many turns the coil has...the impedance will simply be the length of the wire, not its inductance, since you're dealing with DC). Be sure that minimal heat is generated if wire is used as a resistor. Enamel wire can withstand heat the best. Plastic and rubber insulated wires are poor choices.

Several 1 ohm 10 watt resistors in parallel might be another option (possibly a better one). These can be found at Radio Shack. Parallel enough to bring the voltage to where it should be. Place some electrolytics prior to the resistor (whatever the resistor may be), and some after it.

For a more permanent conversion (something that can fit under a table, or inside the radio), a heavy duty 6.3 volt filament transformer (www.tubesandmore.com) and a heavy duty rectifier (perhaps several 4 ampere bridge rectifiers in parallel) will do the trick. You might need a little more voltage, say 7 or 8 volts, due to the heavy current drain. Even with a lot of electrolytics filtering the DC, the current drop may be significant.

But then, after writing all of this, I took a peek at your schematic again, and it shows a total current draw of only a little more than 1 ampere. One 4 ampere bridge rectifer (found at Radio Shack) and one 3 ampere 6.3 volt filament transformer should be adequate. Use a 7 or 8 volt transformer, if available, if current draw is too much at 6.3 volts (bogs down rectifier), or use a 12 volt transformer with suitable dropping resistors, if no 7 or 8 volt transformers are available. Another solution to hot high current resistors on the DC supply is to put a higher resistance resistor on the primary of the transformer. This won't afford filtering in the DC circuit, though.

Be sure to never disconnect the vibrator supply with the radio running. The dropping resistor you select will not drop the current appropriately to the tube filaments with the absence of vibrator current draw. If you are worried about such a situation, it is best to use separate resistors for the vibrator supply and the filaments. This way a lack of current draw at the vibrator supply is less likely to severely affect the current availablility to the tube filaments.

Thomas

Thomas.. don't you think one could find a properly sized wall-wart 6vdc supply that would do the job?

YOu know....that would probably work, too (or radio shack). My brain works in reverse, though. I come up with the most technical method (or strange method), and slowly think of less technical things, and didn't even bother to think of those little plug in supplies. I've been realizing more and more that I think in reverse. Usually whatever I come up with, someone else comes up with, but in reverse of the way I explain it.

Coming across a 1.5 ampere supply might be somewhat difficult, though, depending upon where you go. Be sure to filter well. Instead of cracking open the supply, put some 3500 MFD condensers inside of the radio. Also, it may be necessary to crack open the supply to put .1 MFD condensers across the diodes, if hum is still a problem (remember your transmitter).

T.

Thomas... I said a 6vdc wall-wart...then you said "or radio shack"

Did you think I meant WalMart? .. It is the first time I've use the term "wall-wart".. expecting that it resembled a wart on the wall... but now you're making me think it's another term for WalMart"... is it?
...now I have no idea... lol

I thought you meant Wall Mart. Didn't see the W.

Aside from thinking backwards, I think inverted, upside down, and inside out. I have dislexia. My memory is very good, but very short. An 85 year old probably has a better memory than I have, though my grandmother was as good as I, or worse, and I got the saying from her. I probably got my memory from her, too.

T.

:i just bought a 6volt battert U-51 G.E. radio., it says its a 6 volt radio, is there a easy diagram of how to convert it to AC. if theres a diagram around, please email to me., southerncontry@yahoo.com

Paul,
I received a new Radio Daze catalog yesterday. On page 75 they have what they call an "A-B-C Battery Eliminator Power Supply Kit". They claim that it will be available in November for $84.95.

Will

a-

AES sells an A-B-C battery eliminator kit for $53.95 (K-101A). The "A" supply is rated at 1.5A, but at 6V, that linear regulator will get quite hot. For continuous operation, I'd suggest a larger heat sink for the regulator, and even so, this unit will be a little "dicey."

The RadioDaze kit that Will identified will be rated at 2.5A. Better specs if you can wait until November when it becomes available.

:I received a new Radio Daze catalog yesterday. On page 75 they have what they call an "A-B-C Battery Eliminator Power Supply Kit". They claim that it will be available in November for $84.95.
:
:Will
:
:
:
:
:
:
:a-

I built my own eliminator for my Radiola 16. I started with 1.5 ampere regulators. They got very hot. If I wired three in parallel, they'd work continuously sometimes. I had heat sinks on them. I feed them 12 volts and regulate for 6. I do this because it gives more flexibility with line current variation, and it eliminates more hum. Someone said that I should put in 6 to get out 6 and then they'll run cooler. That doesn't give me much flexibility, though. I then purchased a 3 ampere regulator. Keep in mind that 6 01A tubes draw 1.5 amperes. The regulator got extremely hot and then would cut out (thermal protection). It had a single little heat sink on it. I then took a thick (3/16 inch thick) strap of metal and mounted three heat sinks to it and then mounted the assembly to the regulator. It works for a while, and then it cuts out. It's cutting out more and more easily as time goes on. I'm about ready to call it a day.

I think that if you want to make a 1.5 ampere regulator give you 1.5 amperes, you have to put a sheet of aluminum on it that's bigger than your hand. Aluminum is best because it conducts heat better than steel. I wish that companies would rate their devices more appropriately. 1.5 ampere and 3 ampere regulators are poor excuses for what they're rated at.

Thomas

Hi

When using regulators you need a heatsink to dissipate power across the LM317. Using them in parallel isn't the answer unless more current is needed. Then you will still have a problem of balancing current between regulators. Using a LM350 or LM338 regulator at the same current still requires the same size heat sink.

Reducing input voltage will help keep a regulator cool. Ideal input for 6 volts regulated would be around 9 volts AC to a bridge rectifier. When you use 12 volts more power will be dissipated across the regulator.

You must keep voltage across the regulator above its drop out level. This will be around 3 volts. If voltage across the regulator is 4 volts @ 1.5 amps that's 6 watts to dissipate on a heat sink. If 6 volts is dropped @ 1.5 amps, 9 watts.

Norm

:I built my own eliminator for my Radiola 16. I started with 1.5 ampere regulators. They got very hot. If I wired three in parallel, they'd work continuously sometimes. I had heat sinks on them. I feed them 12 volts and regulate for 6. I do this because it gives more flexibility with line current variation, and it eliminates more hum. Someone said that I should put in 6 to get out 6 and then they'll run cooler. That doesn't give me much flexibility, though. I then purchased a 3 ampere regulator. Keep in mind that 6 01A tubes draw 1.5 amperes. The regulator got extremely hot and then would cut out (thermal protection). It had a single little heat sink on it. I then took a thick (3/16 inch thick) strap of metal and mounted three heat sinks to it and then mounted the assembly to the regulator. It works for a while, and then it cuts out. It's cutting out more and more easily as time goes on. I'm about ready to call it a day.
:
:I think that if you want to make a 1.5 ampere regulator give you 1.5 amperes, you have to put a sheet of aluminum on it that's bigger than your hand. Aluminum is best because it conducts heat better than steel. I wish that companies would rate their devices more appropriately. 1.5 ampere and 3 ampere regulators are poor excuses for what they're rated at.
:
:Thomas

Has any one tried using the LM317 to drive a transistor, such as 2N3055? The 2N3055 would be mounted on a heatsink. Take a look at the National Semiconductor website for the LM317 for the data sheet. It will list a couple of options for using the 317/338/350 to drive high current/high voltage transistors. Also, you would want to fuse the input of the circuit (if 1.5 Amps is required, select say a 3 Amp fuse) to protect the radio in case the transistor should every short and feed the input voltage into the radio.

David S.

:Hi
:
: When using regulators you need a heatsink to dissipate power across the LM317. Using them in parallel isn't the answer unless more current is needed. Then you will still have a problem of balancing current between regulators. Using a LM350 or LM338 regulator at the same current still requires the same size heat sink.
:
: Reducing input voltage will help keep a regulator cool. Ideal input for 6 volts regulated would be around 9 volts AC to a bridge rectifier. When you use 12 volts more power will be dissipated across the regulator.
:
: You must keep voltage across the regulator above its drop out level. This will be around 3 volts. If voltage across the regulator is 4 volts @ 1.5 amps that's 6 watts to dissipate on a heat sink. If 6 volts is dropped @ 1.5 amps, 9 watts.
:
:Norm
:
:
:
::I built my own eliminator for my Radiola 16. I started with 1.5 ampere regulators. They got very hot. If I wired three in parallel, they'd work continuously sometimes. I had heat sinks on them. I feed them 12 volts and regulate for 6. I do this because it gives more flexibility with line current variation, and it eliminates more hum. Someone said that I should put in 6 to get out 6 and then they'll run cooler. That doesn't give me much flexibility, though. I then purchased a 3 ampere regulator. Keep in mind that 6 01A tubes draw 1.5 amperes. The regulator got extremely hot and then would cut out (thermal protection). It had a single little heat sink on it. I then took a thick (3/16 inch thick) strap of metal and mounted three heat sinks to it and then mounted the assembly to the regulator. It works for a while, and then it cuts out. It's cutting out more and more easily as time goes on. I'm about ready to call it a day.
::
::I think that if you want to make a 1.5 ampere regulator give you 1.5 amperes, you have to put a sheet of aluminum on it that's bigger than your hand. Aluminum is best because it conducts heat better than steel. I wish that companies would rate their devices more appropriately. 1.5 ampere and 3 ampere regulators are poor excuses for what they're rated at.
::
::Thomas

Hi David

Good idea, a LM317 can be used driving a 2N3055 as emitter follower. Works well but now you need a good heatsink on the 2N3055. Can't get away from the heat.

Norm

:Has any one tried using the LM317 to drive a transistor, such as 2N3055? The 2N3055 would be mounted on a heatsink. Take a look at the National Semiconductor website for the LM317 for the data sheet. It will list a couple of options for using the 317/338/350 to drive high current/high voltage transistors. Also, you would want to fuse the input of the circuit (if 1.5 Amps is required, select say a 3 Amp fuse) to protect the radio in case the transistor should every short and feed the input voltage into the radio.
:
:David S.
:
::Hi
::
:: When using regulators you need a heatsink to dissipate power across the LM317. Using them in parallel isn't the answer unless more current is needed. Then you will still have a problem of balancing current between regulators. Using a LM350 or LM338 regulator at the same current still requires the same size heat sink.
::
:: Reducing input voltage will help keep a regulator cool. Ideal input for 6 volts regulated would be around 9 volts AC to a bridge rectifier. When you use 12 volts more power will be dissipated across the regulator.
::
:: You must keep voltage across the regulator above its drop out level. This will be around 3 volts. If voltage across the regulator is 4 volts @ 1.5 amps that's 6 watts to dissipate on a heat sink. If 6 volts is dropped @ 1.5 amps, 9 watts.
::
::Norm
::
::
::
:::I built my own eliminator for my Radiola 16. I started with 1.5 ampere regulators. They got very hot. If I wired three in parallel, they'd work continuously sometimes. I had heat sinks on them. I feed them 12 volts and regulate for 6. I do this because it gives more flexibility with line current variation, and it eliminates more hum. Someone said that I should put in 6 to get out 6 and then they'll run cooler. That doesn't give me much flexibility, though. I then purchased a 3 ampere regulator. Keep in mind that 6 01A tubes draw 1.5 amperes. The regulator got extremely hot and then would cut out (thermal protection). It had a single little heat sink on it. I then took a thick (3/16 inch thick) strap of metal and mounted three heat sinks to it and then mounted the assembly to the regulator. It works for a while, and then it cuts out. It's cutting out more and more easily as time goes on. I'm about ready to call it a day.
:::
:::I think that if you want to make a 1.5 ampere regulator give you 1.5 amperes, you have to put a sheet of aluminum on it that's bigger than your hand. Aluminum is best because it conducts heat better than steel. I wish that companies would rate their devices more appropriately. 1.5 ampere and 3 ampere regulators are poor excuses for what they're rated at.
:::
:::Thomas

There no way of getting around using a heatsink, unless you can locate some way to keep the components cool, maybe a bath of liquid nitrogen?

David S

:Hi David
:
: Good idea, a LM317 can be used driving a 2N3055 as emitter follower. Works well but now you need a good heatsink on the 2N3055. Can't get away from the heat.
:
:Norm
:
::Has any one tried using the LM317 to drive a transistor, such as 2N3055? The 2N3055 would be mounted on a heatsink. Take a look at the National Semiconductor website for the LM317 for the data sheet. It will list a couple of options for using the 317/338/350 to drive high current/high voltage transistors. Also, you would want to fuse the input of the circuit (if 1.5 Amps is required, select say a 3 Amp fuse) to protect the radio in case the transistor should every short and feed the input voltage into the radio.
::
::David S.
::
:::Hi
:::
::: When using regulators you need a heatsink to dissipate power across the LM317. Using them in parallel isn't the answer unless more current is needed. Then you will still have a problem of balancing current between regulators. Using a LM350 or LM338 regulator at the same current still requires the same size heat sink.
:::
::: Reducing input voltage will help keep a regulator cool. Ideal input for 6 volts regulated would be around 9 volts AC to a bridge rectifier. When you use 12 volts more power will be dissipated across the regulator.
:::
::: You must keep voltage across the regulator above its drop out level. This will be around 3 volts. If voltage across the regulator is 4 volts @ 1.5 amps that's 6 watts to dissipate on a heat sink. If 6 volts is dropped @ 1.5 amps, 9 watts.
:::
:::Norm
:::
:::
:::
::::I built my own eliminator for my Radiola 16. I started with 1.5 ampere regulators. They got very hot. If I wired three in parallel, they'd work continuously sometimes. I had heat sinks on them. I feed them 12 volts and regulate for 6. I do this because it gives more flexibility with line current variation, and it eliminates more hum. Someone said that I should put in 6 to get out 6 and then they'll run cooler. That doesn't give me much flexibility, though. I then purchased a 3 ampere regulator. Keep in mind that 6 01A tubes draw 1.5 amperes. The regulator got extremely hot and then would cut out (thermal protection). It had a single little heat sink on it. I then took a thick (3/16 inch thick) strap of metal and mounted three heat sinks to it and then mounted the assembly to the regulator. It works for a while, and then it cuts out. It's cutting out more and more easily as time goes on. I'm about ready to call it a day.
::::
::::I think that if you want to make a 1.5 ampere regulator give you 1.5 amperes, you have to put a sheet of aluminum on it that's bigger than your hand. Aluminum is best because it conducts heat better than steel. I wish that companies would rate their devices more appropriately. 1.5 ampere and 3 ampere regulators are poor excuses for what they're rated at.
::::
::::Thomas

I have used the extra pass transistor method and it works well. The large heat sink is required. Mount the LM317 on a seperate location as the pass transistor will make the LM317 drift thermally. Use bypass capacitors close to the regualtor to prevent oscillation. The fuse is a good idea but may not be fast enough to protect the radio. Use what is called a crowbar over voltage protection (Sense circuit triggers a SCR which is across the output). Keep the input voltage at least 2.5 volts above the output voltage at full load. Look at the ripple voltage and make sure it doesn't dip below the output volatge. If you use too high an input voltage you will generate much heat (Just ask young Thomas). Best wishes.

MRO

:There no way of getting around using a heatsink, unless you can locate some way to keep the components cool, maybe a bath of liquid nitrogen?
:
:David S
:
::Hi David
::
:: Good idea, a LM317 can be used driving a 2N3055 as emitter follower. Works well but now you need a good heatsink on the 2N3055. Can't get away from the heat.
::
::Norm
::
:::Has any one tried using the LM317 to drive a transistor, such as 2N3055? The 2N3055 would be mounted on a heatsink. Take a look at the National Semiconductor website for the LM317 for the data sheet. It will list a couple of options for using the 317/338/350 to drive high current/high voltage transistors. Also, you would want to fuse the input of the circuit (if 1.5 Amps is required, select say a 3 Amp fuse) to protect the radio in case the transistor should every short and feed the input voltage into the radio.
:::
:::David S.
:::
::::Hi
::::
:::: When using regulators you need a heatsink to dissipate power across the LM317. Using them in parallel isn't the answer unless more current is needed. Then you will still have a problem of balancing current between regulators. Using a LM350 or LM338 regulator at the same current still requires the same size heat sink.
::::
:::: Reducing input voltage will help keep a regulator cool. Ideal input for 6 volts regulated would be around 9 volts AC to a bridge rectifier. When you use 12 volts more power will be dissipated across the regulator.
::::
:::: You must keep voltage across the regulator above its drop out level. This will be around 3 volts. If voltage across the regulator is 4 volts @ 1.5 amps that's 6 watts to dissipate on a heat sink. If 6 volts is dropped @ 1.5 amps, 9 watts.
::::
::::Norm
::::
::::
::::
:::::I built my own eliminator for my Radiola 16. I started with 1.5 ampere regulators. They got very hot. If I wired three in parallel, they'd work continuously sometimes. I had heat sinks on them. I feed them 12 volts and regulate for 6. I do this because it gives more flexibility with line current variation, and it eliminates more hum. Someone said that I should put in 6 to get out 6 and then they'll run cooler. That doesn't give me much flexibility, though. I then purchased a 3 ampere regulator. Keep in mind that 6 01A tubes draw 1.5 amperes. The regulator got extremely hot and then would cut out (thermal protection). It had a single little heat sink on it. I then took a thick (3/16 inch thick) strap of metal and mounted three heat sinks to it and then mounted the assembly to the regulator. It works for a while, and then it cuts out. It's cutting out more and more easily as time goes on. I'm about ready to call it a day.
:::::
:::::I think that if you want to make a 1.5 ampere regulator give you 1.5 amperes, you have to put a sheet of aluminum on it that's bigger than your hand. Aluminum is best because it conducts heat better than steel. I wish that companies would rate their devices more appropriately. 1.5 ampere and 3 ampere regulators are poor excuses for what they're rated at.
:::::
:::::Thomas

WEll, you can put the 2N3055s in parallel. NO problem balancing them, since they don't regulate or switch. Some will pass slightly more current, and some will pass slightly less, with any given setting. The collective result is all that is needed. Heat sinks will still be needed, but each one won't get as hot.

T.