I have a headphone amp/splitter device that runs from a 9V AC, 750mA wall wart.

I would like to get the device running from a 12V DC supply.

I have taken a look inside the unit and it basically splits the 9V AC supply into +9v DC, -9v DC and 0V before it goes into the main circuitry.

I carried out a simple test with 2 9V batteries wired to create a dual polarity supply and it works fine.

I don't want to run it from 9V batteries so I need a circuit to provide a 9V DC dual polarity supply from a single 12V DC source. I would use a ICL7660 to create the dual dual polarity but I don't think it will be able to pass enough current for the amp.

I did think about stepping up the 12v to 24v then using a simple resistor divider to get +12V, -12V and ground then running each supply through a 7809 and a 7909. Would that work?

Is there a cleaner/better way to get this amp to run from a 12V DC source?


1 Answer 1


The power rails probably don't need accurate regulation but they will need to be clean of noise. I'd consider using a flyback regulator with two output windings that can generate both dc rails then use a bit more LC filtering to smooth ithem more making it suitable for audio.

There are plenty of chips from linear technology that fit the bill.


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