Hi Larryi, the reason Delta Sigma (1 bit) based chips were bought out also are not just more suitable for other applications but are also less than 1/10 the price to manufacturer. As there are no R2R ladder resistors to be finely laser trimmed, which is a very expensive part of Multibit dac chip manufacturing.
Yes the Naim 555 which I would also love to own, uses the same R2R Multibit dacs.
If you search around many hi-end manufacturers are now starting to go back to Multibit dacs for Redbook even if they have to make their own discrete ones, because they know now to do Redbook (PCM) conversion "bit perfect" you have to use Multibit. As Delta Sigma is just an approximation (facsimile). And also that DSD was a bit of a hoax anyway which needs Delta Sigma dacs to be converted.
If you really want to hear "hi rez" forget DSD, listen to a soundtrack from the now defunct DVD-A (which is 24bit PCM) through a dac which has our 24bit PCM1704 converters, it is a truly magical experience. Such a shame DVD-A never took off, probably because they needed the expensive to manufacture R2R Multibit dacs to convert it "bit perfect", which was around the time Delta Sigma (1 bit) was being pushed onto the market.
Also there now maybe DXD audio trying to get into the market (which should sound as good as DVD-A), and it’s also true 24bit PCM and needs, (yes you guessed it) Multibit dacs to convert it "Bit Perfect", one can only hope!!