The organ for the Lutheran Theological Seminary in Gettysburg, Pennsylvania, was built by Andover in 1980 as Opus 84. The case was designed by Donald H. Olson, drawing on the work of the early American organ builder David Tannenberg, to complement the Georgian building. The case is poplar, oak and birch, painted to match the building, and shades were carved by Dennis Olsen of the Andover firm. Stop knobs are turned rosewood with hand engraved ivory labels.

Key and stop action are mechanical throughout in a design by Benjamin Mague. The Great division is located in the center of the case with the Chamade division directly beneath it. The Pedal is divided at either side of the main case and the Swell division is immediately behind the Great division. The couplers are located on hitch-down pedals as are the Tremolo and Zimbelstern.

The tonal design by Robert J. Reich provides an instrument which will fulfill all of the musical functions of the Lutheran liturgy as well as accompanying choirs and soloists. It is also designed as a teaching and recital instrument. The stoplist was drawn up in consultation with the Organ Committee of the Seminary.

In 1996, the Seminary once again contacted Andover to build a small organ to supplement its Opus 84. They needed a portable organ for continuo and accompaniment, and for taking on the road with the Seminary choir.

Jay Harold Zoller, organ designer for Andover, both designed and built the portable. It is a four-stop positiv organ, with a 54-note compass. Tonal design and finishing was done by John W. Morlock. The keyboard shifts one note for early music at A 415. Its appearance is Colonial Georgian. Sturdy casters make it easy to move, while folding doors protect it in transit. A 110 volt blower is built into the case. The organ measures 57 inches wide, 33 inches deep, by 50 inches high.

The portable was installed in the spring of 1998. Rev. Stephen P. Folkemer, Music Director at the Seminary, liked the looks of the instrument so much that he requested it be installed in a ruckpositiv position near the larger organ. The two organs were connected by an "Orgamat" system from Laukhuff in Germany, in order to play the small organ from the main console if desired. The orgamat, designed for use in tuning, sits on the keyboard of the small organ. It is activated by Opto-electronic contacts on the chamade keyboard.