Electronic – Connecting two power supplies with almost like voltages to an amplifier in parallel

12vamplifierpower supply

I have recently been working on a custom sound system in my living room. For the subwoofer, I am using a 1000W amplifier. This is currently running off of a 12V computer power supply that outputs around 650W (The power supply shuts off at a certain volume because of lack of power). I have another power supply (not a computer power supply) that is 500W but has a voltage of 13.5V, not 12. I've read that this voltage is actually better for running car audio equipment and I am using another 13.5V power supply for the head unit to power the highs and mids.

I am wondering if it would be possible for me to connect these two power supplies in parallel to increase the power to this amplifier since they are both safe voltages. Would this be possible? Would I need to use a resistor to match voltages? Or is this just not a good idea altogether?

Update: This is car audio equipment so high power ratings should not be a shock.

Best Answer

Let me put this as an answer rather than a continuation of comments.
Adding diode to supplies, something like this. Now you'll want some beefy diodes, maybe 30 to 60 amps. And probably Schottkies, maybe something from this page. With heat sinks. RE: power supply adjustment. Hopefully there is some adjustment so that you can set the voltage for each supply to be about equal. (Actually you'll want the voltage after each diode under load to be equal.) Getting exactly 12V is not important.

I do worry, that I'm giving advice to a musician and not an electronics "geek". I hope you understand what you are doing. Do you have a way to measure the voltage? Do you know why I picked the diodes I did? And why the heatsink?