How do I make a +12V and -12V power supply?

Other Hardware General Electronics
1

Hi all!

How do I make a +12V and -12V power supply? I only have high power 12v power supplies, but I need a +12V and -12V power supply for an audio amplifier. How would I make that? Preferably from 12v power supplies if that is possible.

Thanks in advance!

2

Your post was MOVED to its current location as it is more suitable

3

What do you consider "make" to be? Are you wanting to buy the individual components and connect them together? Or you wanting to convert one of your existing supplies to have the + as the ground rather than the -? Which ever, you need to begin with a schematic of either a proposed power supply or the schematic for one of your existing supplies.
IF you are starting from scratch and depending on the power requirements, you can build both into a single unit.
What do you consider high power?

4

Yes, I would like to do that if possible.

My existing supplies are the generic ones inside the metal cage type thing. I have two 12A and two 5A.

Well, my audio amplifier can output 40W on 4 channels, so a total of 160W out. So at 12V in, that would need to be 13.5A in. FYI, the amplifier can have a max of 18V.

Basically I need a +-9V supply (I think :thinking:), or is that a +-12V supply I need?

5

Then I don't understand what you are really proposing. You cannot get 13.5 amps from a 12 amp Chinese power supply. My limited experience with them is you can get 12 volts from them or you can get 12 amps from them, but you cannot get both 12 volts and 12 amps at the same time. The voltage drops considerably long before 12 amps is produced.
Why did you ask about a - 12 volt supply?

6

Like This?

+ 12V -+ 12V -

7

That is what I was thinking. Then the center tap is GND, the left or positive is +12V, and the right or negative, is -12V, right?

8

try it, do you have multimeter? I personally would build one from scratch using toroidal transformer, well I already built one for my audio

9

Oh, thanks for that info. I haven't actually had a use for all 12 amps yet. I do have a 12V 24A power supply. It is US made from a US company and is mainly used for LEDs. Would that do any good?

10

Build a toroidal transformer? I was going to buy one off of amazon, but it cost $150, way too much for my budget :money_mouth_face:.

11

yeah build transformer :roll_eyes:

12

I wouldn't even know where to start. I considered it, but it seems like it is very possible for something bad to happen with that much power :grimacing:.

13

you start with selecting transformer for your power requirements and voltage, keeping in mind that when rectified you will get almost 1.4 times higher voltage. Then you choose rectifier bridge of appropriate current, an array of capacitors and a regulator (or not). actually scratch that. first you google how to build dual voltage power supply

1 Like
14

I googled a lot of different things, and only found one helpful site. Ill try that search also.

I got this from this website:

1280×1749 129 KB

image
image1280×1749 298 KB

15

looks good, mine also has selector 230/115

16

OK. Also could you help with another audio question I have? I posted it here Low Pass RC Filter - #11 by kgray9

Thanks

17

Right now I just have my amplifier powered by a +12V 5A power supply. The sound is very loud already. What would change if I used a 12A power supply? Volume?

18

Most likely, nothing will change. Where is the volume control set? Maximum volume? The maximum current will ONLY be used when necessary on peaks of the sound.

19

So, the sound will have more depth, i.e. more volume on the peaks?

Yes.

20

I have no idea what depth has to do with sound. You can check to output voltage with an oscilloscope. If the sound volume peaks are no longer peaks, but are flat-topped or rounded off, then more current capacity is needed. If not, then all is working as designed.

1 Like