Effects pecal doesn't seem to do much

I bought a boss cs 3 compression sustainer off ebay yesterday. On the boss website, they have audio samples of certain settings. I did the same settings as the "thick sounds" setting on the website and mine sounds nowhere near what theirs sounds like. Is this because i have a 15 watt practice amp? I heard that you need to crank up the volume, so I maxed out the volume on my amp and it sounds kind of the same as playing without the pedal. The pedal works by the way.