I am trying to turn my rear surround speakers from plug in AC to a battery powered DC. I would like to create a smal circuit board that I can mounted to the back of the speakers (hopefully). The input is rated 120V, 60Hz, 11W so it's not a lot of power.

1) I have searched the web for some basic DC-AC inverter designs but am a bit confused. I keep finding videos etc. for 12VDC to 220V AC but I can't seem to find anything rated 110-120V output. Is there a reason for this?

example design: https://www.electroschematics.com/9155/12v-to-220v-voltage-inverter/

2) The parts seem relatively easy to come by but I would like to utilize a 9V or some AA or AAA batteries if possible. Can someone point me in the direction of a more detailed design guide?

3) How do you size the RC components to get 60hz? It seems every design I've found they use different equations. From my college days I seem to remember the f = 1/RC but when I test this on designs it never works out. Any insight?

Thanks in advance.

 

It would be easiest to open up your speakers, and see what voltage is being used, by measuring it , chances are it will have a Transformer or smpsu to drop it down to maybe 12Vdc or higher.

That way you can choose a battery pack.

 

Hmm I will give that a shot as I was just thinking that a 9V or AA batteries capacity likely wouldn't be able to power the speakers for very long anyway.

 

I am trying to turn my rear surround speakers from plug in AC to a battery powered DC.

Are you talking about amplified house speakers, used with a TV set? Don't most of those use a "wall wart" type power supply? Most but not all wall warts output DC any way. If not wall wart powered it probably has an internal step down transformer bridge diode for power. May get better help if you would give a brand and model of the speakers or if you have it a link to them on the web.

 

There is no power adapter external to the speaker, just the AC cable directly to the wall. However there may be something within the speaker like you mentioned. The link for the rear speakers is here: https://www.sony.com/electronics/sound-bars/sa-z9r

 

If the internal speaker power supply is more then 12 volts you could hack the inside and use a dc to dc converter module or just buy a small 12 volt DC inverter like this one from Amazon for 14.00
https://images-na.ssl-images-amazon.com/images/I/5166-NgI+GL._AC_US327_FMwebp_QL65_.jpg
SG

 

In the tech specs, a speaker is capable of 50 W output, but draws only 11 W from the power line. At least one of these two numbers is incorrect.

ak

 

In the tech specs, a speaker is capable of 50 W output, but draws only 11 W from the power line. At least one of these two numbers is incorrect.

Yes, I noticed this too. Ebay addvert...

• Power output (total): 100W
• Power consumption in operation: 11W

Isn't it amazing how these audio people can completely solve the world's power problems

Still, I too would vote for an internal 12V supply as a possibility. Open them up and measure the output volts of the power supply to see.

 

That would require a fairly large 12V battery though, correct?

 

That would require a fairly large 12V battery though, correct?

Your putting these in you car, correct? So what is wrong with the car battery? It is powering the stereo/radio and the entire car, you think the add on speakers will overload it?

 

Isn't it amazing how these audio people can completely solve the world's power problems

It's the "oxygen free copper wire". Everyone knows that.

 

I just now read this thread. An audio amplifier MUST be using DC for the actual amplifier circuit, and so adding a circuit to supply AC from batteries would be terribly less efficient. If your plan is to run them in a car, then the first step is to open them up and find what the DC supply voltage is. BUT why "surround sound" speakers anyway? Or is this for something totally different, like a home theater in a dorm room? Like many times previously, more information will usually allow somebody who reads the post to provide a very good answer. Most of us a very poor mind-readers, and so we need more information.