Not much can be said with certainty about the earliest organ — now known as the Hinsz main organ — in the Bovenkerk. It is generally assumed that the church acquired a large organ built between 1520 and 1523 by Johan van Kovelens (or J. van Covelen). The oldest pipework in the instrument — particularly the 4′ and 2′ flutes of the Bovenwerk — likely dates from Jan Morlet (1629). In 1676, Jan Slegel completed a new organ, incorporating material from the earlier instrument. Between 1694 and 1712, Johan Duyschot made some modifications and was responsible for its maintenance.

From 1741 to 1743, Albertus Anthoni Hinsz carried out extensive work on the organ: he designed a new case, replaced all wind ducts, built new windchests and action, and slightly expanded the stoplist. This became the largest organ Hinsz ever built.

Between 1788 and 1790, H.H. Freytag and F.C. Schnitger Jr. added a free pedal division with 8 stops and a Brustwerk with 4 stops, playable from the Bovenwerk manual. They relocated the Dulcian 8′ from the Rugwerk to the new Brustwerk and placed a Fagott 16′ on the Rugwerk in its place.

Throughout the 19th century, organ builders Van Gruisen, Scheuer, and Naber made further changes. In 1866, the Kampen-based organ builder Zwier van Dijk provided the Brustwerk with its own manual and added several stops.

Source: debovenkerk.nl