In 2023, Kevin Keim emailed Hendrik Ahrend, the son of Jürgen Ahrend, who built the Burns House tracker organ, the first outside of Europe.

“I know this is remote possibility, but should you ever learn of one of your Uncle Klaus’ harpsichords becoming available, would you let me know?” 

Only hours later, Hendrik replied: “I’m amazed you asked me this question. Only two days ago, I heard for the very first time ever one of Uncle Klaus’s rare instruments becoming available, when Timothy Roberts in London contacted me for advice about finding a new home for a harpsichord.”

Hendrik put me in touch with Timothy, a fine player who inherited the instrument from Martin Birnstingl, a British surgeon and husband of the architect Renate Prince. They had commissioned Klaus Ahrend to build this harpsichord for their famous Modernist flat in Hampstead. Birnstingl wanted a fine harpsichord that would emulate the best of historic instruments in sound, but be modernist in design sensibility. In particular, they insisted the case would be unadorned and unpainted.

Klaus Ahrend apprenticed in the workshop of Martin Skowroneck. In 1962, the acclaimed harpsichordist Gustav Leonhardt commissioned Skowroneck to build an instrument based on the work of Johannes Daniel Dulcken (1706–1757), whose instruments represented the culmination of Flemish harpsichord-making. After studying original Dulcken instruments throughout Europe, Skowroneck built an instrument that Leonhardt made famous in his many recordings, especially of Bach’s solo keyboard music. 

Klaus Ahrend took three years to design and build the Birnstingl harpsichord. The instrument’s spine measures 8’6”, so the strings could proportionally be lengthened—instead of thickened for the bass—thus achieving a superior clarity of tone. Its two manuals have a five-octave range from FF to f', with the usual disposition 8'+8'+4', a sliding coupler, and a buff stop on the upper manual.