Downsizing is a fashionable concept in the current economic climate, though there are certain things that can't be skimped – late-Romantic Russian symphonies being a case in point. Nevertheless, Thomas Zehetmair's Tchaikovsky cycle suggests that a chamber-size orchestra can be viable in this repertoire. Zehetmair has delivered sprightly accounts of the second and third symphonies, and a slightly welterweight fourth, even with some reinforcements to the strings. The forces assembled for the fifth truly pared things to the bone (Tchaikovsky with four cellos – it's like facing Barcelona with no midfield), yet it might have been the most persuasive interpretation to date.

Tchaikovsky characterised the fifth symphony as "a complete resignation before fate"; and the cyclical transformation of its lugubrious theme is the sound of a man falling into a deep despair before hauling himself out of it. Zehetmair doesn't quite pursue the vibrato-less asceticism of a Norrington, nor does he have any patience with false sentiment or emotional indulgence. Individual themes shone out with particular iridescence, not least Peter Francomb's burnished horn solo in the second movement. Tchaikovsky's struggle with symphonic form is well documented: "What I write has always a mountain of padding," he confessed. Zehetmair and the Northern Sinfonia strip away all extraneous material to present Tchaikovsky unstuffed.

Beethoven's first Piano Concerto is more squarely located within the ensemble's comfort zone, though Jonathan Biss's performance still seemed to go out on a limb, pecking at the keyboard with his nose inches from his knuckles, in a manner sometimes reminiscent of Glenn Gould. Yet Biss's style is fluid and pleasingly unmannered: the largo – the most expansive of Beethoven's slow movements – luxuriated in a languorous interchange between the piano and Francesco Scola's clarinet in a stately dance of serpentine beauty.