Rocketfish rf-acnt2 ipod wow!!!!!

I took a recommendation found a cheap one of these.  Plugged in the 30 pin to bottom of ipod, rca into preamp, and holy fuc*in wow,.  Why does the volume (gain) go so much higher now???

before i was using the 3.5mm jack to rca on preamp, but man is this amazing, the volume is insane now, bass, mid, highs. Wtf just happened?  

Did i bypass the output of the ipod, using the amps gain from my stereo?  

Help me understand

thanks