First, nothing wrong with using the PS3 as a Bluray player. It does an excellent job.
Secondly, yes, you should hear a very large difference in sound quality. Standard Dolby Digital and DTS are multi-channel systems that utilize what is referred to as lossy compression. What this means is that to make room for the multi-channel soundtracks included on standard DVD's Dolby and DTS had to severely compress the audio of these soundtracks so that they would fit on the disc. This type of lossy compression discarded a large amount of the actual information found in the soundtrack. The new Hi-def codecs such as Dolby Digital HD or DTS Master Audio use what is referred to as lossless compression. These systems while still basically a compressed format use much less compression than the standard Dolby or DTS plus they utilize much higher sampling rates than the standard codecs. What this all adds up to is top notch multi-channel sound from a Bluray player that can pass these signals through its multi- analogue outputs, as the Oppo does. Sound fully comparable to and sometimes superior to SCAD or DVD-Audio.
Secondly, yes, you should hear a very large difference in sound quality. Standard Dolby Digital and DTS are multi-channel systems that utilize what is referred to as lossy compression. What this means is that to make room for the multi-channel soundtracks included on standard DVD's Dolby and DTS had to severely compress the audio of these soundtracks so that they would fit on the disc. This type of lossy compression discarded a large amount of the actual information found in the soundtrack. The new Hi-def codecs such as Dolby Digital HD or DTS Master Audio use what is referred to as lossless compression. These systems while still basically a compressed format use much less compression than the standard Dolby or DTS plus they utilize much higher sampling rates than the standard codecs. What this all adds up to is top notch multi-channel sound from a Bluray player that can pass these signals through its multi- analogue outputs, as the Oppo does. Sound fully comparable to and sometimes superior to SCAD or DVD-Audio.