Bruel Kjaer 1612 schematic

These filters are popular i guess , i know very little about these and it seems all the service manuals from this company are just business to few keeping it away from public ,it's nice to see inductors in a filter tho i never used them ,people say they make lot of color ,if anyone has info on filters from this company feel free to share it if you will ,it would be something to clone these ,even not vcf