Hi, I'm just wondering about the difference between 24bit dac VS 32bit dac.
I don't know why some people are obsessed with 32bit
Is there any difference between them?
It's not the output stage of the DAC that's 32 bit... there is no DAC IC in production that has better than 24 bit analog resolution. The 32 bit number is just in reference to the digital pipeline within the DAC. The idea is that at every stage from filtering onwards, there are fewer numerical errors if you have a 32 bit pipeline (keep in mind this is all integer math, not floating point), and there is no need to apply any dither at all. Some 24 bit DACs use a 28 bit accumulator internally for similar reasons. With a 32 bit pipeline, you can also do volume control digitally and not lose real resolution -- at least in theory, but keep in mind that the analog stage ultimately is limited to <24 bit resolution.
It's not the sort of thing that will necessarily affect the sound (though low quality digital filters like the DF1704 arguably do have audible effects), but it's nice to have. 384kHz PCM DACs are similar... there are virtually no recordings at that rate and it's almost certainly inaudible over lower sampling rates, but it gives you the flexibility to implement an 8x oversampling digital filter in software if you're the kind of person who has a background in signal processing.