In our competition-based, profit-driven society where better pay, promotions and new opportunities regularly prompt so many to chase new jobs, long-term, carefully maintained professional relationships are sadly a scarce phenomenon. It seems to be distinctly old fashioned to stay in the same job for several decades. Nobody would ever accuse Richard Tognetti of being old fashioned, yet he has been Artistic Director of the Australian Chamber Orchestra for twenty-five years. He has led from the front desk of the first violins, organised recordings, tours and festivals, and shaped the orchestra’s playing style, repertoire, and artistic image by creating a diverse range of innovative programmes.

In fact, for their current national tour quite the opposite happened as the ACO took a bow to the past, to a quarter of a century ago when, during Tognetti’s first year as concert master, Frans Brüggen was asked to conduct Mozart’s last three symphonies. (It is a poignant coincidence that this current tour will finish only one day before the first anniversary of Brüggen’s death.) That same programme was repeated on the weekend in Sydney: the Symphony in E flat major, K543 and in G minor, K550 was followed after the interval by Symphony no. 41 in C major "Jupiter", K551.

The experiences of twenty-five years have offered innumerable occasions for Tognetti to continuously define and refine his interpretation of late 18th-century music (the ACO also recorded all the Mozart violin concertos with Tognetti as the soloist). His musical ideas are overall much more radical than those employed by most mainstream orchestras, but he doesn’t follow notions of historical performance practice rigidly either. A bit like his ruffled, ever-boyish hairstyle, the elements don’t always match in a strict sense and the guiding idea may not seem entirely clear, yet in the end a distinct character emerges combined with irresistible panache, and the final product is as convincing as it is congenial.

For this concert, a splendid wind section joined the core membership of the ACO; the wind and brass players performed exclusively on period instruments, while in front of them the strings used their modern instruments. (Despite the obvious attention that had been paid to this potential problem, the string ensemble sounded occasionally slightly too voluminous for the delicate wind melodies.) Some string players played with baroque or classical bows, whereas others worked with modern bows, and there also seemed to be a merry mixture of modern and gut strings. The weight of the cellos was supported by metal endpins (typical for modern instruments) and the bowing and fingering techniques by and large ignored 18th-century well-documented conventions.

None of it diminished the joyfulness of exuberant, self-evident music making. Old or new instruments, playing techniques and performing traditions became agreeable partners, united by the musicality of the players and the strong artistic concept of their leader.

The sound produced was unique, robust and without exception well-articulated. Vibrato became a tool for expressive articulation and thus was selectively used, rather than as a standard tone colour. Not only every symphony but every movement had its own character, expressed partly by Tognetti’s sensitive ear to details and partly by Mozart’s ingenious orchestration - despite the fact that the three symphonies were written back to back within only about six weeks, the composer selected a different mix of wind and brass instruments for each of them.

The contrasts were colourful and bountiful. I had never heard the middle section of the E flat major symphony’s Menuetto movement performed with such effective dissimilarities between flowing legato melodies and brisk, staccato accompaniment. The longing beginning of the G minor Symphony was tossed back into harsh reality by the first tutti entry, led by the deliberately ragged, almost aggressive horns. The repetition of large sections in this symphony (and elsewhere) was never mechanical, but rather a re-imagination with tangible differences. The opening movement of the Jupiter conquered triumphantly with all its C major, march-worthy, trumpet blazing glory – and what a stunning difference it made to the G minor symphony’s languid, pained, quietly passionate beginning! It is a passion that, like a shadow, follows this work throughout, until in the middle of the last movement it becomes a wildly spluttering, unison shriek from the whole orchestra – making use of all but one note of the complete chromatic scale. It was an astonishing compositional feat, performed with astonishing drive and persuasion, one of the highlights of the evening.

Judging by Frans Brüggen’s own recording of these works, he may have had different ideas about them. I still think he would have enjoyed this performance.