Don, I think Adampeter is refering to the Gain levels (4db versus 8db) in the line stage, not phono stage. The original LA150 mk1 used a jumper in the line stage on the line stage circuit board near the gain tubes, one for each channel.
As oppossed to the phono MM vs MC switch of the ops1/ops2 phono preamp.
As oppossed to the phono MM vs MC switch of the ops1/ops2 phono preamp.