As for the sound, a louder volume is probably due to higher output signals on the dac than the original cd player - no big deal. The fact that it sounds cleaner is good - that's what the upgrade is supposed to do. As for the various numbers on the front, those are just telling you what frequency the digital input is running at. It is selected automatically, and it probably always show 44.1kHz, which is the standard for consumer CD format. Studios or midi/computer digital might use some of the other frequencies. I concur with the previous followup as to using the RCA digital connection instead of the Toslink optical. The Toslink might be ok for MD or computer connections, but is not as high fidelity as a 75ohm rca connection. Try a few different cables if you can, we have found digital cables to make almost as much of a difference as the dac itself.