2x18VDC instead of 2x24.4VAC

Discussion in 'The Projects Forum' started by Edmunds, Sep 27, 2010.

  1. Edmunds

    Thread Starter Active Member

    Sep 27, 2010
    Hello all,

    I have trouble finding a suitable converter from 12VDC to 2x at least 12VAC. 2 x 18VAC preferably. I experimented with running DC through a rectifier (a given, difficult to go around them) and this seems to raise the voltage slightly. I have no problem with that, though, so is that ok? Can I use DC instead of AC?


  2. wayneh


    Sep 9, 2010
    Huh? Between the title and description, I can't tell what you want to do. And what do you mean by "2X"?
  3. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    What do you want 12VAC for?

    Do you want 12VAC or 18VAC or 24VAC?

    What are you powering?

    How much current?

    What is the supply for this?
  4. Edmunds

    Thread Starter Active Member

    Sep 27, 2010

    Sorry for being confusing at 03:05AM. Did not realize it was that late :).

    I have solved the problem above by finding and ordering a chinese inverter on ebay at a cost probably lower than the total cost of the parts I would have to buy and the cost of making the PCB. The intention is to power an amplifier in a motorhome, so I have 12VDC available, but the amp I want is TDA-something based and needs two times (hence the 2x) 18VDC or rather -18V 0V +18V config.

    Now, the second problem remains. I need to power the control unit and the preamp from 12VDC battery power as well. In the original setup, it is fed from 14.5VAC secondary of the 220VAC transformer through a rectifier. I checked the current draw and it is never more than 500mA. I also tried to run it on 12VAC, since I happen to have such a wall transformer at home for model trains and it is happily working with no problem. It seems like I need to find a neat circuit to build (cannot be to complex, right?) that would take my 12VDC and convert it into 12VAC, so I would not have to bother with dismantling the amp more than I already have.

    Any circuit designs you can point me to? I do understand the term oscillator and also the term filter and a few others, but and answer like "hook up an LM555 oscilator, a filter and a suitable transformer" won't do - sorry, not there yet. So I need a circuit with schematics, parts list and a PCB layout if possible and finally some description of what, why, how, so I can learn something would score a 10 out of 10 :).

    Thank you for your time,