You know G-Man; this is a linkwitz-riley but it is a three way design. Last year I bought his original x-over board, his boards are only a couple bucks each but I haven't done anything with it yet and If I remmember without looking mine was the po9. I am leafing through the article but I can't find any reference to a model number. Let me search the thing; there has to be a model number somewhere. This article is a really complete and thorough build description with wiring shots and everything. It looks as if you can buy it as a kit but I don't see a source reference. I'll let you know.How's the chip amp project coming?