David,
The supply that you have does produce enough current.? It is a voltage lower than the 13.8 volts supplied by your main rig supply that is reducing the output.
Since purchasing through Amazon, you can try the second power supply to see if it generates too much RF hash (QRM) receiving.? If the interference is high, return it.? I bought a similar supply on eBay, which produced all kinds of noise.? It went into the junk pile as there was no return option.
73
Evan
AC9TU
