The manual indicates it will pass the true analog or digital source....so if you're using analog connections rather than digital then there'd be no DAC processing (at least that's how I would take it).
I did a test with pure direct mode with my Oppo BDP-103 in analog mode and HDMI (audio is set to HDMI 2 on the Oppo) to my Pioneer VSX-1120. Sound quality is slightly better on my receiver. I'm convinced that my receiver slightly degrades analog sound quality because it there are two conversions taking place ( Oppo and VSX-1120) and its not a true pure direct mode. According to the my receiver's manual there is minimal digital treatment in pure direct mode.
That would be three conversions - the Oppo's DAC and the AVR's ADC followed by another DAC. Again, I would be quite surprised if any receiver digitized the analog stereo inputs when set to Pure Direct. Are you saying there's no way to prevent your receiver from digitizing the analog inputs, that it can't simply pass through an analog input to the amplifiers?
I think that there was something wrong with my setup, so when I got home from work today I decided to reset my Pioneer VSX-1120 to default settings and do the calibration settings, now pure direct mode sounds better with analog sources.