awesome! glad to hear you got it working!
One thing ... did you mean to say you put a 10k resistor in series with the amp or did you mean parallel? Having a resistor in series with another load (the amp in this case) will supply the same ammount of current (amps) to both the resistor and the load, but different voltages. So you will have a voltage drop across the resistor and you won't get the full 5v to the amp.
Putting the resistor in parallel to the load will supply the same voltage to both but different currents. In this senerio the resistor acts as acurrent limiting resistor (though the current draw of the other load should be known, and the value for your resistor should be calculated so it is able to limit the current as you wish)
I'm not sure how well you know electronics so I don't mean to offend.