These were part of the recent Group Buy where quite a number of people ordered these along with the ACMP-73 and 81. A lot of people are having hum and hiss problems with theirs so you may want to check on the condition before you purchase. I have an ACMP-73 and 84, 84 is my favorite of the 2, and it is quiet. The eq section on my 73 puts out a small amount of noise which I will need to fix in the future, but the pre section is quiet.
There is a thread in the Low End section, talks about the problems, where you can gather a lot of info on the pre's.