I just wanted to recommend this sampleset by Sonus Paradisi for those of You who might not have had a chance to hear it, let alone play it, yet. Cannot emphasize how much I love this organ!
The instrument in the St. Valentinus and Dionysius church in Kiedrich has the reputation of being the oldest playable organ in Germany. Although that may not be exactly correct, the organ is certainly one of the oldest in Germany, and it contains elements stemming from around 1500.
The independent pedal was added probably in 1722. The restoration done in the 19th century is remarkable, because it is so unlike those performed on many other historical organs at that time. When the Baron John Sutton discovered this instrument on one of his journeys through Europe, he was captivated by its Gothic origin and he supplied the money to "restore" the instrument to its 1500 state.
The last restoration by Kuhn (1985-1987) preserved the state achieved by the previous restoration of John Sutton, emphasizing the Gothic Hauptwerk of the organ as a single manual organ.
The positiv is hidden behind the main organ case in the church tower, thus sounding as an echo-organ, and the modern pedal is also concealed in the church tower behind the organ case.
The Gothic and the neo-Gothic elements blend together exceptionally well in this particular church. The visitor is truly astonished by the church's ambiance when entering the building. The absence of the ecclesiastical baroque, which is so common elsewhere, make this church and its organ absolutely extraordinary.
Some further details on-line: http://www.musiqueorguequebec.ca/orgues/allemagne/kiedrichsv.html
Sample set and knowledge source: Sonus Paradisi