It turns out that the mysterious Stage Lead is just a Studio Lead in a different cabinet with 2x12 (or possibly 4x10) instead of 2x10 speakers. The parallel connected 12 inch speakers were 8 ohms each making a 4 ohm load. 4x10 amps used 16 ohm speakers. Posted here is the schematic and PCB layout from the Studio Lead. The Studio Bass used the same circuit board, the components for the reverb were just left off. The driver transformer is the same as the Concert series.
Edit: Attachments were corrupt so I deleted them. Also attached the Studio Bass or Stage Bass schematic. Keywords Stage Studio Lead Bass schematic layout
