Power supply paralleling 2

To succesfully parallel power supplies, you need less than perfect regulation in order to share the load. The less sophisticated the power supply is, the better it will work. If you had two 10A supplies you would have a better chance. One will always try to supply more current because of a slightly higher voltage or higher gain. So 10A from one and 4 from the other is realistic. Isolating the supplies slightly from each other with either a small resistor or length of wire that develops a 0.2V drop can be helpful.

A common method of commoning supplies is to connect each supply through a diode onto a common bus, which prevents one supply backfeeding the other. As Operahouse says, supplies with slightly loose regulation are better for this kind of application, or you could introduce a resistor of, say, 50mOhm in series with each diode.