I"m no expert but I think Converting 12v DC into 240v AC is going to be a bit of a challenge to do in a DIY Fashion....getting AC from DC is also another challange....
You can buy a power inverter that will convert your 12v DC to 120V AC (The one in My Car puts out 150w AC at 120v AC Max), Most auto Shops have them....If you do this then you won"t have much of a problem because you can simply build your preamp as if you were going to power it from your wall plug but plug it into the Inverter instead.....
You can also get a SMPS which will convert your 12v DC into 120-240v DC , I know the output is DC but I believe that Tubes prefer well filtered DC over AC anyways.....
Good Luck
You can buy a power inverter that will convert your 12v DC to 120V AC (The one in My Car puts out 150w AC at 120v AC Max), Most auto Shops have them....If you do this then you won"t have much of a problem because you can simply build your preamp as if you were going to power it from your wall plug but plug it into the Inverter instead.....
You can also get a SMPS which will convert your 12v DC into 120-240v DC , I know the output is DC but I believe that Tubes prefer well filtered DC over AC anyways.....
Good Luck
Hello ,
Been working on a 250v supply for a 1937 car radio,
they want it converted to 12v and the old 6v transformar was gone anyway. Had an Idea, at work I was using my ac isolated supply with a voltage doubler 2 - 80 mf 450 v caps and 2 diodes,
to make 250 volts for the plate voltage when the vibrator supply didn't work, to run the radio, worked great. Now I thought what about using a 120v ac car inverter, grabed one from stock put 12v on it and wala add the doubler and you get a 12v 250v supply, guess if the ac side is isolated from car chassis you could parallel the outputs to get any voltage. Worked great and you get AC in the car to. Well it did work but thought Id build a suppy anyway, Used 2 MTP3055 MOSFETS, and a dual 120v winding to 24v Centertapped 4 amp, put the 24 v side on the Mosfets and drove them with a SG3525 IC which is made for just that. And put both 120 volt output windings in series with a fullwave bridge and a filter cap. So about 30 dollars including 10 dollar transformar, filter caps, etc.
Easy to find Circuits using SG3525, you can even regulate output with it with a votage divider on output fed back to IC. Thats all for now.
Been working on a 250v supply for a 1937 car radio,
they want it converted to 12v and the old 6v transformar was gone anyway. Had an Idea, at work I was using my ac isolated supply with a voltage doubler 2 - 80 mf 450 v caps and 2 diodes,
to make 250 volts for the plate voltage when the vibrator supply didn't work, to run the radio, worked great. Now I thought what about using a 120v ac car inverter, grabed one from stock put 12v on it and wala add the doubler and you get a 12v 250v supply, guess if the ac side is isolated from car chassis you could parallel the outputs to get any voltage. Worked great and you get AC in the car to. Well it did work but thought Id build a suppy anyway, Used 2 MTP3055 MOSFETS, and a dual 120v winding to 24v Centertapped 4 amp, put the 24 v side on the Mosfets and drove them with a SG3525 IC which is made for just that. And put both 120 volt output windings in series with a fullwave bridge and a filter cap. So about 30 dollars including 10 dollar transformar, filter caps, etc.
Easy to find Circuits using SG3525, you can even regulate output with it with a votage divider on output fed back to IC. Thats all for now.
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