also a secondary question if anyone knows or can refer me to a grade-school answer; I believe the original Marantz chips were SAP16NY & SAP16PY pairs. I see a ebay used set of SAP16PO & SAP16PO chips cheap.

Are these O suffix chips actually the same (mix & match pairs) as the Y suffux ones. My amp has 12 "Y" chips (6 pairs) and I would really like to just replace the bad couple instead of buying a set.