A friend and industry player has recommended that I upgrade a DVD player and then put an external digital-to-analog converter (DAC) between the digital output of the player and the analog input of my processor/preamp. This is supposed to improve the sound of all my CDs as well as DVDs by upsampling at a higher bit rate and frequency (BelCanto2 has 24bit/192kHz). 1. How does a source like an 18bit/48kHz CD get improved just by running through a higher performance DAC? 2. Would the external DAC at 24/192 be noticeably better than using the DAC at 24/48 in my processor? The main question is whether the source limits the output. The claim of my friend is that normal 20bit CDs through this 24/192 DAC sound as good as SACDs played on SACD players. Possible technically?