The son of a minister, Jones studied at Caterham School, in Surrey, and was subsequently a Sterndale Bennett Scholar at the Royal Academy of Music. He volunteered for service in the Second World War but was rejected on the grounds of poor health. Determined to "do his bit", Jones made his debut as a harpsichordist in 1940 at one of Dame Myra Hess's National Gallery concerts, where he continued to appear on a regular basis until 1944. He soon became known as a virtuoso.
Immediately after the war, Jones launched into a series of concerts performing the complete organ works of Bach in London. This was a composer to whom he returned a decade later at the Festival Hall, but to a mixed reaction.
One reviewer said: "It is in resource and in the handling of Allegros that Mr Jones's performances excel." Ten days later, the same newspaper (the reviewers were then anonymous) wrote: "As a player, Mr Jones has a clean technique and an austere taste; his playing of the big Prelude in E flat could only be described as antiseptic." The epithet was not as unjustified as it might sound: while intellectually brilliant, Jones's playing was not renowned for its emotional content. Undeterred, Jones embarked on an annual series of organ recitals at the South Bank which ran for more than 30 years.
Already married and divorced by the end of the Forties, Jones undertook many concerts for violin and harpsichord with his second wife, the violinist Winifred Roberts. Together they toured the world performing neglected music of the baroque era.
Winifred subsequently became the leader of the Geraint Jones Orchestra, which evolved from a series of acclaimed performances of Purcell's Dido and Aeneas with the soprano Kirsten Flagstad and the baritone Thomas Hemsley, conducted by Jones, in the opening season of Bernard Miles's Mermaid Theatre in 1951.
The now historic recording of this Dido and Aeneas - which included Elisabeth Schwarzkopf - was produced by Walter Legge for HMV and was the first of many recordings featuring music by Bach, Handel and Mozart. Among them was the Italian version of Gluck's Alceste, also with Flagstad. Jones's discs won the Grand Prix du Disque in 1959 and 1966.
By 1969 Jones was hitting relatively modern music. With the pianist Stephen Bishop he championed all of Mozart's piano concertos in a 15-month series at the Queen Elizabeth Hall in London. At the end of the final concert in April 1970, the artists returned to the stage to acknowledge the applause and by way of an encore repeated the slow movement of the C major Concerto (K467) but with Jones at the keyboard and Bishop on the rostrum.
During the 1960s and 1970s Jones came to be seen as more of a musical statesman. He was artistic director of several festivals, including the Lake District Festival which he founded in 1960, Salisbury Festival (1973- 77) and Manchester Festival (1977-87). But it was to the Kirckman Concert Society, founded in 1963 to provide a platform for outstanding young artists, that he devoted much of his time and energy.
His 35 years as director of the Kirckman Concert Society marked him out as a man with a great knack for spotting talented youngsters. Stephen Bishop was just one of Jones's proteges. The singer Mitsuko Shirai and the pianist Hartmut Holl, and more recently the Emperor String Quartet, were other beneficiaries of the society's largesse.
Away from the platform Jones was very highly thought of as an organ designer. Like Bach he was a connoisseur not just of music but of instruments, and he was involved in the construction of organs at the Royal Northern College of Music, St Andrew's University, the Royal Academy of Music and the Academy for Performing Arts in Hong Kong.
A true Welshman in manner and character, Jones forever had a twinkle in his eye and had a mischievous sense of humour. He adored smart cars, pretty women, and parties, where he was a shrewd people watcher. He retained a large and assorted circle of friends until the very end of his life.
Geraint Iwan Jones, musician: born Porth, Glamorgan 16 May 1917; FRAM 1954; Professor, Royal Academy of Music 1961-88; married 1940 M.A. Kemp (one daughter), 1949 Winifred Roberts; died London 3 May 1998.