Currently i'm using PC PSU to power up my car amp and pc speaker, please refer to the thread below.

My Thread

From the pic, you can see i actually fed 12V to the amp by ATX 4pin connector (CPU).

So far the setup is running fine, and no overheat issue also (touch by hand the casing temp is like in shut down mode),
but noticed the +12V voltage is drop to 11.3V (no load 11.7V) during heavy bass/drag bass, i checked others unused 4 pin Molex 12V, the voltage is constant.

My question is:

Can i short all the 12V (yellow) line together, so that each rail will provide equal current to the setup, so that the voltage is more stable?

Thanks in advance.