I have never seen the 555, or any other sony for that matter referred to as an upsampler.
I would guess the 555 works like my SCD-1.
For CD's, it outputs 44khz which can be fed to an upsampling DAC.
For non-hybrid SACD's, there is no digital output
For hybrid SACD's, I can play the CD layer and get digital output from that.
Unless you are looking for the convenience of a carousel, the price difference in moving up to an XA and ES 777's may be worthwhile consideration relative to buying a DAC. These two sound much better than the 555 or the 9000, especially due to the quality of their analog output stages. The 777's/SCD-1 are world class and would not really not be improved by a DAC until you reach the megabuck range. I found my hotrodded SCD-1, in all cases but one (a $4700 dac) sounded better on it's own.
That being said, I found a few dac's that I think provide an improvement over the 555 at a lower cost. The Upsampling Bel Canto DAC 1, 1.1 or 2.0 are all excellent price/performance as is the Modwright Perpetual Technologies units. I owned the 1.0 and 2.0 for a time. I've never heard anything that can compete with them in the 1K class. The older DAC's, even though high end ones may have superior analog sections, seem to have a rougher 'digital sound' compared to more modern converters.
I would guess the 555 works like my SCD-1.
For CD's, it outputs 44khz which can be fed to an upsampling DAC.
For non-hybrid SACD's, there is no digital output
For hybrid SACD's, I can play the CD layer and get digital output from that.
Unless you are looking for the convenience of a carousel, the price difference in moving up to an XA and ES 777's may be worthwhile consideration relative to buying a DAC. These two sound much better than the 555 or the 9000, especially due to the quality of their analog output stages. The 777's/SCD-1 are world class and would not really not be improved by a DAC until you reach the megabuck range. I found my hotrodded SCD-1, in all cases but one (a $4700 dac) sounded better on it's own.
That being said, I found a few dac's that I think provide an improvement over the 555 at a lower cost. The Upsampling Bel Canto DAC 1, 1.1 or 2.0 are all excellent price/performance as is the Modwright Perpetual Technologies units. I owned the 1.0 and 2.0 for a time. I've never heard anything that can compete with them in the 1K class. The older DAC's, even though high end ones may have superior analog sections, seem to have a rougher 'digital sound' compared to more modern converters.