[1] Both father and son are mentioned in the German translation of Charles Burney's The Present State of Music in Germany, the Netherlands, and United Provinces (1773): "Hasse, father and son, of Hamburg, both dead; their harpsichords and clavichords are much sought after".

His business may have been continued by Johann Christoffer Krogmann, a builder of fortepianos who was married to Hass's daughter Margaretha Catharina.

[1] Hass's instruments are cleverly designed, strongly built, richly decorated and finely finished.

[2]: 238 He built large clavichords of the kind that post-Baroque composers such as Carl Philipp Emanuel Bach wrote for, with good tone and volume, and capable of expressive bebung.

A massive instrument by Johann Adolph with two manuals and five sets of strings (16', 2 × 8', 4', 2'), with tortoiseshell natural keys and ivory-topped sharps, dates from 1760–1761, and is now in the Yale University Collection of Musical Instruments in New Haven, Connecticut.