What is a ac adapter converter?
A converter takes energy from the wall in one format and turns it into another. So, in Argentina the ac adapter is 220-240v, 50 Hz, AC. That means the voltage is 220 to 240 and it comes in 50 alternating cycles per second. For comparison the United States of America is 120 volts at 60hz. You can see different standard ac adapter measure from around the world at http://www.kropla.com/electric2.htm
Now, will that work for you? Most electrical products should say in tiny little writing something like
Input: 100-240v, 50-60hz.
Output: 6.5-18.5v, 4.6A max.
So, look at the rating for the country you are going to and then look at the acceptable inputs on your device. If your device says it only works from 100-120 volts and you are going to a place that puts out 220 volts you will need a converter to turn the 220 into 120.
What is a ac adapter?
An ac adapter just takes the plug on your current device and changes the shape of the metal so it will connect to another plug. So, if the country you are going to has different shaped plugs (hint: they usually do unless they are direct neighbors) then you will always need an adapter.
Ultimate combo: converter, adapter, ac adapter strip
So, you're bringing along 2 adapters, but a slightly better alternative is to bring 1 adapter and a ac adapter strip that you plug into your adapter and then you plug your 3 or 4 devices into that one ac adapter strip.
I have had dozens of times in airports where there are people huddled like hawks around laptop ac adapter outlets waiting for someone to finish charging or board their plane. I just unplug someone, pop in my little triple-outlet-ac adapter-strip, plug the first person back into mine, and get a grateful friend in the form of a person who can now use the third outlet in my strip.