Audio Systems: car power amp/speaker pop, ac dc adapter, pop pop pop

Question
I'm testing a Yamaha YPA-700 Power Amplifier. I'm using a 12v 500ma AC/DC adapter to power it. When I connect the power to the Remote power positive terminal, my speakers make a very loud POP! POP! POP! noise until I disconnect the power from that terminal. Is that because the power supply I'm using doesn't put out enough amps? If not, what else could it be? I'm using a little CD player into the channel 1 & 2 line level inputs of the amplifier with 2 small 100watt/8ohm speakers out the channel 1 & 2 speaker outputs. I've used the same input/speaker/power setup testing other car power amps with no problems.

Answer
To answer the 1st question... Possibly yes.
The amp could be bad but those old 700's are very large power amps.

"I've used the same input/speaker/power setup testing other car power amps with no problems."
Many amps that size (and old) need more than a 1/2 ampere to power up (and much more to crank them up).
Some of the newer high-power headunits pull enough amperes to shut down that power supply as well.

Check your ground and hope.. or run the PS across a decent 12V battery to augment the PS current rating and try again. If it does not work at that point, you may have a bad amp.

JM