Electrical – How to get +6V and -6V out of 12V PSU

guitar-pedaloperational-amplifierpower supply

I am designing a guitar pedal using OpAmps, and i need to feed them with +6V and -6V (beucase the musical signal is senoidal centered in 0V). I need to use a 12V DC PSU for the pedal, and i need to convert to positive and negative voltage. If possible it would be better if it was +12V and -12V but if its not possible i can work with +-6V. I also need this to be reasonably simple and cheap.

Best Answer

Ground is an illusion. We choose a node and decide we're going to call it 0V, and give it the magical name ground. If you create a reference of 6V from your 12V supply, and call it ground, your 12V supply just became +/-6V.

Of course, ground is also assumed to be low impedance, so you'll have trouble if you create it using a 100K voltage divider and then try to use it as a current return. Because of that, we generally call it Vref, and thus remember to take into account its current limitations relative to the supply.

If there's a DC offset between Vref and your I/O, capacitors will resolve it nicely.