This elaborate action with sostenuto pedal and soft pedal compensator is by an unknown maker.
Upright action model with sostenuto
Upright action model with sostenuto, slow
Close up of sostenuto mechanism
Close up of sostenuto mechanism, slow
Compensator close up
Compensator close up, slow
Upright action model with sostenuto and compensator (maker unknown)Upright action model with sostenuto and compensatorUpright action model with sostenuto and compensator – close up of backUpright action model with sostenuto and compensator – close upUpright action model with sostenuto and compensator – close upUpright action model with sostenuto and compensator – close up