Johann (Georg) Andreas Stein (16 May 1728 in Heidelsheim – 29 February 1792 in Augsburg) was an outstanding German maker of keyboard instruments, a central figure in the history of the piano.

He was primarily responsible for the design of the so-called German hammer action. Pianos with this hammer action, or its more developed form known as the Viennese action, may be said to be appropriate for the performance of the piano music of Haydn, Mozart, and the early works of Beethoven and Schubert.^[1]

Stein was born in 1728 in Heidelsheim in the Upper Palatinate.^[2] He died in Augsburg in 1792. He learned his trade as an organ builder from his father in Heidelsheim and from August 1748 to January 1749 as a journeyman at two workshops, those of Johann Andreas Silbermann in Strasbourg and of Franz Jakob Späth in Regensburg. Johann Andreas Silbermann was the eldest of the four sons of Andreas Silbermann, the elder brother of Gottfried Silbermann. Stein settled in Augsburg, probably in 1750 and became a citizen in 1756 or 1757, the latter the year in which he completed his magnificent organ for the so-called Barfüßerkirche in Augsburg. In the same year he became organist at the church. According to a letter he wrote, he gave up organ building in the 1760s in order to devote himself to stringed keyboard instruments. His first contact with piano making may have occurred in the Späth workshop, not in the Silbermann workshop.

As a stringed keyboard instrument maker Stein built clavichords, harpsichords and pianos. He also built some more extraordinary keyboard instruments including the "Poli-Toni-Clavichordium" (described in the Augsburg Intelligenzblatt in 1769) that combined a large harpsichord having four choirs of strings (registration 8', 8', 8', 16') with a piano. He also built (1772) the "Melodica," a small organ in which the player's touch could alter volume, which could be used with a harpsichord or a piano or on a separate manual of an organ or simply as a solo instrument. The importance of the Melodica, of which Stein may only have made a few prototypes, lies in Stein's own 1772 description. In that published description he expressed his dissatisfaction with keyboard instruments in general because they did not allow of expressivity in the manner of the human voice, the violin and the trombone.

The 1769 description of the expressive possibilities of the Poli-Tono-Clavichordium nonetheless shows Stein's confidence in stringed keyboard instruments that in the end led him to the invention of his so-called German hammer action shortly before 1780. He also built "vis-à-vis" instruments with a piano and a harpsichord facing one another in a single case. In both the surviving examples (Verona 1777, Naples 1783), the player of the harpsichord (8', 8', 8', 16' in Verona, 8' quill, 8' leather, 4' quill in Naples) can also couple the piano action at the other end on one of the harpsichord keyboards. The Verona instrument has hand stops for engaging and disengaging the stops, in the manner of an organ or a German harpsichord, whereas the Naples instrument has knee levers in the manner of French harpsichords.

Stein travelled twice to Paris and once to Vienna. He also made trips to other cities in Germany and Switzerland to deliver instruments as evidenced in his notebook.^[3] The hammer action in the 1777 Vis-à-vis is unique in Stein's oeuvre, that in the 1783 Vis-à-vis is Stein's so-called German action.

Two clavichords by Stein survive, one of them, now in the Budapest National Museum, was bought by Leopold Mozart for practising while travelling. One instrument combining a piano and a single rank of organ pipes survives in Gothenburg’s Historical Museum. About fifteen Hammerflügel (wing-shaped pianos) bearing Stein's label survive, ranging in date from 1780 to 1794 (sic). The making of those of after about 1790 would have been supervised by Nannette, Stein's daughter. Of the fifteen, two are privately owned (1782 and 1783).

The instrument shown above is not by Stein but probably by Louis Dulcken. Apart from the music desk, typical of Dulcken's work, the instrument has the appearance of a piano by Stein. Many such instruments built after Stein, some with fake labels, exist.

Stein was the founder of an important piano-making dynasty. His daughter Nannette (Augsburg, 1769 - Vienna 1833) took on the leadership of her father's firm in about 1790 when her father had become too ill to continue. In 1794, Nannette, together with her husband Andreas Streicher (1761–1833), who she married in the same year, and her brother Matthäus Stein (1776–1842), moved her family’s piano-making firm from Augsburg, where it was founded by her father, to Vienna, and continued the family business under her husband's name, Streicher.

In the Autumn of 1802 the siblings, who inscribed their instruments with the name Frère et Sœur Stein in Wien, separated. Nannette then inscribed her instruments Nannette Streicher née Stein in Wien. Some innovations were made in about 1805 but by 1807 she had developed her father’s small five-octave piano, shaped like a harpsichord, into an impressive grand piano of six-and-a-half octaves. Some more improvements were made by 1811, but after that date her design was maintained largely unchanged until Johann Baptist Streicher (1796–1871), her son, became joint owner of the firm with his mother in 1823.

The firm continued after Nannette’s death under her son and after his death in 1871, under his son Emil. Emil’s son, the composer Theodor Streicher, owned the Hammerflügel of 1808 by Nannette Streicher in the collection of the Germanisches Nationalmuseum (inv. no. MIR 1117). In 1896 the firm ceased production, just over one hundred years after the move to Vienna.

Meanwhile, after the separation of the siblings, Nannette's brother, known as André Stein, also continued to build pianos. In 1796 André married Maria Theresia Dischler (1769–1855), an event marked by a letter from Beethoven including his congratulations. The letter mentions a piano by Nannette Streicher that he had on loan for an Accademie. The letter suggests that the sound of the instrument was too weak for Beethoven's needs. André Stein obtained his citizenship of Vienna and became a master piano maker there in 1803. Despite Andreas Streicher’s adverse comments (mostly of a personal nature to do with André Stein’s reputedly difficult character), André Stein made fine instruments and developed an individual style thought by some to exceed that of his sister Nannette. He flourished in the 1820s.

In 1828 Friedrich Wieck (1785–1873) acquired a Hammerflügel by André Stein for his daughter Clara (1819–1896). She later married Robert Schumann, and her instrument by Stein is preserved today in the Robert Schumann House in Zwickau, and pictured on the German DM 100 banknote issued in 1989.^[11]

From Beethoven’s conversation books it is clear that André Stein was well known to Beethoven and helped him not only by tuning and maintaining instruments but also by making a large horn to amplify the sound of the piano. Matthäus Andreas died in May 1842 in the Mondscheinhaus, the building bought by his only son Carl Andreas Stein (1797–1863) from the renowned piano maker Conrad Graf (1782–1851) in 1841.

Carl Andreas continued in his father’s footsteps as a piano maker but also made a name as a composer and as a pianist. Numerous instruments by André Stein survive, including more than twenty Hammerflügel dating from about 1803 to at least 1838, at least 26 square pianos,^[12] probably all after 1815, and two upright Hammerflügel. Most of these pianos are in public collections.^[13]

Recordings made with replicas of instruments by Stein

• Ronald Brautigam. Ludwig van Beethoven. Complete works for solo piano, Vol.9. Played on a replica of Stein piano made by Paul McNulty. Label: BIS
• Alexei Lubimov and his colleagues. Ludwig van Beethoven. Complete piano sonatas. Played on copies of Stein, Walter, Graf, Buchholtz instruments made by Paul McNulty. Label: Moscow Conservatory Records

• Timeline of harpsichord makers