yep…the PCM70 uses delay taps, that is 2 groups of 3 delays, with a common feedback path in each group. I have a PCM80 where things are very similar.
I have just worked on 2 versions of the algorithm, one for the 4000 and the other for the 7600/8000 platform, where it sounds even better, owing to a DELAY_FX module that works as a modular delay taps.
I hope to post your version tomorrow. The bigger one will be in the next OS (7600/8000).
P.S. Thanks for all those links! Interesting how people are still going nuts for all that old stuff.