Hi folks, was just talking to Doug Oade about the PMD660 and PMD671, and pointed out a confusing sentence (a cut-and-paste error, he said) on the PMD671 updates page of the Oade site. Basically the AM for both models is the choice for non-amplified music and quieter sources, but will seldom overload at say, front row of orchestra. The ACM has a lower gain range (the stated gain numbers *are* correct, referenced to 0dBu) to avoid overloading, though that can still happen, with very high SPLs. The quality of each mod (AC and ACM) is about the same, just optimised for different sources. This was very helpful, as now I understand that the AC will give me better S/N for my particular uses. He will fix the site soon, not sure when. Just for reference, Doug also confirmed that either Advanced or Advanced Concert Mod on the 660 will yield better sonics than the Basic Mod on the 671. Great guy! Happy holidays to all.