Do I need an external DAC to play my music files?

What resolution your DAC plays back in depends on the file structure and resolution of your music files. If you have ripped a standard CD, they will most likely be 44.1K/16 bit. Some DACs will "upsample" this resolution to higher bit rates, and some find this upsampling to be a detriment rather than an advantage. So playback at the native 44.1/16 is not always a bad thing.

Other high resolution music files are available from download sources or commercially (like the Apple Beatles release) and this music is in a higher resolution format. Higher resolution files are probably never "downsampled" to 44.1/16, but are played back at their native resolution.

So it all depends on your files and whether the Integra automatically upsamples them or not.

If you took the USB stick and plugged it into the Oppo and then connected the Oppo to your preamp using analog cables, you would be using the Oppo's DACs, which are quite good...

-RW-

When I play my music files on the Integra, the song is displayed at whatever the bit rate (192/256/320,etc) and then 44.1kHz. And I've read that there are DACs that take those files and boosts them from 44.1 to 192. So what is out there that does this (relatively cheap) and/or is this even worth the trouble?

I believe that Kal (Kr4) has reviewed the Integra and I know he has experience with the Oppo. Maybe he'll jump in with some advice on the relative merits of their DACs and how the upsampling on each works.