There are three elements to today's column, and they are all linked.

The past 10 months have been an intensive period in his native Scotland for composer James MacMillan. While his global career continues to spiral, events on his home turf have been concentrated, not least in the creation of his own festival, the Cumnock Tryst. Last October we heard the UK premiere performances of his Third Piano Concerto, a stunning piece, blindingly played by Jean-Yves Thibaudet with the RSNO and Peter Oundjian.

Then, in January, came an extraordinary event. MacMillan revealed that, in the course of having a bit of a clear-up, he had unearthed piles of music written in his youth and his student years. These, which included choral pieces, orchestral pieces and chamber music, were, to a degree, the work of a young man learning his craft, as well as a student preparing portfolios for degrees. They had ended up in a drawer as the ceaseless wave of demand for new works spread universally after 1990.

But MacMillan, in the course of clearing up, looked at them again. He recognised much that was already his own voice, and a number of strands that seemed to him prophetic of what was to follow as his career moved towards the end of the 1980s, before exploding in 1990, first nationally, then, with startling rapidity, globally. The unearthing and editing of some of those early pieces culminated in January with a remarkable BBC SSO concert where we heard the first performances of The Keening and the Symphonic Study.

In the run-up to that revelatory concert, I interviewed MacMillan about his finding, revising and evaluating these early pieces; I came away with a notion that there might be more to follow. There is; and here comes some of it. This week Delphian Records released a new album with the Edinburgh Quartet (of which MacMillan is patron) playing music from very early in his career to more recent compositions. Now, I stress, this is not a CD review: I have listened to the disc only twice, and it needs more work. But I have to tell you this is breathtaking stuff: at first run-through I was gobsmacked.

The disc includes MacMillan's earliest piece for string quartet, written in 1982 while he was a student in Durham. It's a Wagnerian-inspired piece, entitled Etwas Zuruckhaltend, packed with the big motifs from The Ring, especially Wagner's Fate and Redemption themes. But the whole thing is laced with that already unmistakable MacMillan scrunch - in 1982! He revised it in 2009, it was premiered in 2010 and this is its first recording.

And there is a cracker in Visions Of A November Spring, which gives the album its title. MacMillan's first published string quartet, Visions was written in 1988 and revised in 1991, so it coincides with that huge rush of visionary creativity that swept MacMillan through the back end of the 1980s and into the worldwide glare of the 1990s. And you can hear it right through this fantastic piece, which is saturated with the colours, flavours and specific quotations from his breakthrough orchestral masterpiece, Tryst. The rest of the music on the new CD can wait until I have absorbed it before reviewing the album.

I said there were three linked elements to this column. Briefly: the Edinburgh Quartet has undergone significant personnel changes within the last seven years. Tristan Gurney took over leadership in 2007; violist Jessica Beeston joined the group in 2011; and Gordon Bragg was appointed second violin in March last year. To judge from what I have already heard on the new album, the group has never been stronger. There is powerhouse playing throughout the ensemble, and from top to bottom of the texture.

And the third element? It's Paul Baxter's Delphian Records, long-established as a great Scottish company and unswerving supporter of Scottish music and composers. But this recording, produced and engineered by Baxter himself, has a blistering impact that reinforces Delphian's championship and commitment to the art form and the musicians who make it happen.

Absolutely essential listening.