Exactly what I'm wondering as well. How much difference does the DAC make in reality. I've heard Nuked-SC55 doesn't actually emulate the DAC of the real SC-55 series, but they still sound very, very similar to me.
The DAC on the SC-55 vs SC-55mkII vs Nuked (none emulated I believe?) doesn't make THAT big of a difference, although I haven't studied that as closely as others I've mentioned in this post.
What does make a difference is that the 880 and 88Pro use *substantially* different DACs, different generations, different technologies. They characterise the sound very differently. You can easily find people discussing the Roland JV-1080 vs JV-2080 sound, and those two uses DAC's that weren't THAT different (actually, the same as the ones used in the SC-55mkII and 88Pro respectively, and both are good). The PCM69 DAC in the 88 and 88Pro (and JV-880 and 2080) is highly regarded for its era, particularly in sytnhs.
The new-style AK brand DAC's used in Roland equipment from 2000 onwards, SC-880/JV-1010/XV-5080 etc sound more "hi-fi" but definitely lose some of the warmth and analog sound of the older units. (See also the 8820, which uses a new style BB PCM brand DAC, and the 8850, which uses a new style AK DAC, I definitely prefer the sound of the 8820.) The way I would describe the difference is synths using the AK DAC sound "neutered", something tangible is lost.
it makes no difference you can hear. this was a professional musical instrument, not a toy. whatever dac they use is going to be fine.
I disagree. I mean, you're right in the sense that one isn't "good" and one "bad", both will be fine for general purposes. But if you care about the 'best', or at least, most enjoyable sound, an 88Pro will sound superior to an 880 - at least in my and other people's opinions. Sound Canvases, JVs and old Roland gear weren't meant to sound "hi-fi" (and featured non hi-fi samples), they were meant to impart warm characteristics and lushness on the audio, giving a desirable, memorable output. The more modern DAC's present the audio too "uncoloured" and something is lost. But this is my opinion, check YouTube, audio demos or better yet hear the actual units to make your own opinions. For me, it's fairly noticeable after years of hearing demos of the SC-880 vs SC-88/Pro or JV-1010 vs JV-1080/2080.