{TABLE} Sonata in E minor Op 90 ......... Beethoven Waltzes D145 .................... Schubert Bagatelles OP 126 ............... Beethoven Sonata in C minor D958 .......... Schubert {/TABLE} THE pianist John O'Conor, who will be 50 tomorrow, undertook his musical celebration of the occasion a little in advance of the actual date, with a recital at the National Concert Hall last night.

O'Conor's greatest early triumphs came in Vienna, where he took first prize at the Beethoven Competition in 1973, and his NCH programmed reflected his ongoing engagement with the music of two of that city's greatest masters, Beethoven and Schubert.

It was in the early 1970s, a few years before the competition win, that I first encountered his playing. My earliest recollections are of a performance style much more personalised in gesture and expression than it is today. On his return from Vienna, I remember noting that his music making had shifted significantly away from the play as you feel tendencies to be heard from many of his Irish colleagues at that time and towards a style of greater focus and tighter musical discipline.

These characteristics are still keenly felt in his handling of Beethoven. The two movement Sonata in E minor, Op. 90, opened the birthday concert, taut and surely propelled in the first movement, and with an easy, unforced lyricism fin the second.

The O'Conor approach, which favours brightness of mood (without neglecting urgency) and tenderness of expression over elements of conflict, uncertainty or darkness, is fully serviceable in the late Bagatelles of Beethoven, though the outcome lacks the sense of questing strangeness that the pieces show in other, more probing hands.

In Schubert, the formula is not always so successful. In the late C minor Sonata the layering of the music into dominating tune and subsidiary accompaniment was simply too thoroughgoing. To take Just one instance, the effect of the extraordinary chromaticism at the end of the first movement's development section was simply lost with the left hand so relentlessly emphasised at the expense of the right. The group of waltzes in the first half fared better, the louder ones a bit gruff, perhaps, but the lighter ones by no means short on charm.

The performer's easy listening charm was in even richer supply in the two encores, Chopin's Nocturne in E flat, Op. 9 No. 2, and Mozart's Rondo Alla Turca, which without difficulty brought the capacity audience to its feet.