Car audio at home with computer PSU- how to keep memory?

[fergug]

Hi everyone

I've been doing a lot of reading about this issue and I was hoping I could get some clarification.

I want to power a car stereo receiver (head unit only, max 10A draw) at home with a computer psu.
I have 12v wires to the red ACC wire and yellow constant wire, with grounds connected and the green wire hooked up to a switch with a ground wire to turn the unit on and off.

The problem is that I can get it to switch on, but once I turn it off it loses all presets.

My understanding is that the memory requires 12V at some unknown, but low current. The power supply has a 5v stand-by rail that I think is on all the time. however, I obviously need 12V!
I'm thinking of buying a psu with a 12v stand by rail- something like this...

http/www.ebay.com.au/itm/261751787402?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

The problem is that assuming this 12vsb is always on, it will only provide a small amount of current. The ACC line is just for switching the unit on, so so how do I connect the high current 12v rail? Can I connect the 12vsb and high current 12v rails to the yellow constant wire somehow- ie with diodes?

Also, can anyone confirm for me that the stand by rails are actually on all the time?

If not are there any other solutions?

I don't want to leave it on all the time!

thanks for your help in advance

Grant

 

[Someone Somewhere]

Seriously, just get an actual 12V dedicated supply and leave it on.

Then switch the aux feed to the head unit (or even just use the button on the front). Don't bother switching the power supply; they tend to have fairly low standby power. Just make sure you get a fanless one.