Hello, I am building a boom box with a battery and I have a tube preamplifier that runs on 12 volts ac from a seperate transformer inside. My goal is tp make the tube preamp usable with the battery(lead acid). How would I go about converting the DC Signal to Ac?

 

It's called a power inverter.

 

Trace out the 12VAC circuit and see if you can just supply it with DC from the battery, even if you have to use a boost converter.
Without circuit info your question is not simple to get a real answer.

 

If it's just for the heaters, you can use DC, if it's for the HT rail you will need an oscillator/inverter to step up to the higher voltage.

 

If it's just for the heaters, you can use DC, if it's for the HT rail you will need an oscillator/inverter to step up to the higher voltage.

It will be just for the tube preamplifier.

 

If you want to build a battery operated boom box, ditch the tube preamp and use a Class-D solid state amplifier.

 

Hello,

It would even be possible to use tubes on 12 Volts only:
http://www.sophtamps.ca/mambo/index.php?option=com_content&task=view&id=25&Itemid=37

(don't expect much power from it).

Bertus

 

You really need to find the circuit so we can advise you with some accuracy.

 

Hello, sorry that it seems like that I have gone AWOL, but after some thinking. I'm just going to save the tube preamp for a later build that does not run on battery. Even with the inverter in the build, literally everything would have to be routed with even more transformers and switches making the build really impractical in the long run. Problems were like these below.

You really need to find the circuit so we can advise you with some accuracy.

The company that the tube preamplifier comes from has no documentation on circuit designs when it comes to the tube preamplifier, even on internet sources.

Trace out the 12VAC circuit and see if you can just supply it with DC from the battery

If it's just for the heaters, you can use DC, if it's for the HT rail you will need an oscillator/inverter to step up to the higher voltage.

Hello,

It would even be possible to use tubes on 12 Volts only:
http://www.sophtamps.ca/mambo/index.php?option=com_content&task=view&id=25&Itemid=37

(don't expect much power from it).

Bertus

When I did try out the preamplifier on DC, it did work and heat up, but the distortion at half-volume and above was easily noticeable and very bad.

If you want to build a battery operated boom box, ditch the tube preamp and use a Class-D solid state amplifier.

After considering everything that would have to happen to actually make the tube preamplifier work with the battery as stated above, it would just be really impractical and costly.

All in all, thank you all for your help on this topic

Cody