running 12v ac device on 12v dc

[ben19901]

Hey guys I'm building a portable music desk which runs off of an optima yellow top car battery. Problem is my mixer has a 12v AC input from a plugpack transformer (wall-wart to the US). I was wondering if running 12v dc straight into it would be fine. The desk has 2 pioneer cd/tuner car stereos, the small mixer and a kenwood 2x60w amplifier for output. Its a great little setup once its finished but yeah this is the only hold up.

 

[audioguru2]

Hi Ben,
The peak voltage of 12VAC is 17V and a full-wave rectifier will drop it to an unregulated supply of 15.5VDC. The output voltage of the wall-wart might be higher.

You might be able to connect 12VDC to the 12VAC input but it would make an unregulated supply of only 10.5DC. The output voltage of a car battery is a little higher.
The mixer might not work with a voltage so low.

 

[Hero999]

It probably also uses a voltage doubler circuit to generate both positive an negative voltages.

Making an inverter to get 12VAC from 12VDC is possible but not simple.

First you need to convert 12VDC to 17VDC, then use an h-bridge and oscillator to convert it to AC.

 

[Kevin Weddle]

Power inverters, which are sold in stores, are more reliable and won't damage the mixer. You might want to have the circuit designed and funtioning before testing it out on the mixer.