This is the face Melville's Billy Budd might have grown in manhood but for the fatal hesitation that cut across the power of song and tempted him to his one act of violence. Arguably, Harold Budd is the more purely American hero, with even less of the old Adam around the eyes and smile; it isn't a face that could have come from the poisoned Old World; unlike his fictional namesake, too, he speaks with a calm definition and the only stammers in his musical progress have been the self-willed ones.

LA-born in 1936, "I grew up listening to cowboy music on the radio, sweet stuff". The deepest influences, as any good Freudian will tell you, take the longest while to work out. In recent years, Budd has gone back with confidence to explore the emotional and structural possibilities of popular forms. His most recent album, Lovely Thunder (EG), features one long track recorded collaboratively at The Cocteau Twins' studio. Earlier, he'd worked on some of the more sensuous ‘Ambient’ projects with Brian Eno.

Back in the early days, though, during stints as a student at San Fernando Valley State College and as a faculty member at Cal Arts, he'd bid fair to become the very foretopman of the conceptual avant garde, capable in 1970 of such confidently Cagey gestures as The Candy-Apple Revision, which consists of a single, sustained Db major chord (helpfully scored 'for any instrument(s)').

"Of all those early pieces, that's the one that still gives me some pride and for which I feel quite a lot of affection. That's partly because it represented a point of no return with that kind of music. What do you do after something like that? An F# minor piece? It represented a full stop and a fresh start."

After 1972 Budd worked increasingly at a conception of the studio as itself an instrument and one capable of an articulation as complex as an orchestra and as single-minded as that sweet chord.

"Before coming over to Europe, I'd been working in a friend's new Synclavier studio. The first time, I came up with something that I really liked – where it came from I don't know. But I'm not at ease with so much technology. I was able, over a while, to work out all the possibilities, but even then I'm not so obsessed with the purely technical parts of it as not to want to take the piece away and play it on piano in front of a real audience."

I’d started out by quoting to him Gavin Bryars's comment that modern audiences and critics alike are less afraid of complexity than of sentimentality. Doesn't the same thing apply in some way to the kind of lushly romantic music Budd has produced since 1970, music which has often been dismissed out of hand as anti-intellectual mood effects?

"I have enormous respect for Gavin" - they worked together on Budd's album The Pavilion of Dreams - "and would certainly take notice of anything he said…"

The tail-off suggests that he doesn't on this occasion agree. It may well be that the opposition of complexity and sensuous directness is not one that he can swallow. The music on Lovely Thunder and notably the long, deceptively simple "Gipsy Violin", reveals an awareness of texture, of the spatial relationships of sound, which makes its sensuousness seem as far from sentimentality as the Imagists' ideal of an emotional and intellectual complex communicated in an instant of time.

"I want my music to be pretty, and that is pretty, not beautiful in the sense of . . ." The Romantics' sublime? "Yes, not that, but pretty."

Sentimentalism is the risk you run when you reach for Wordsworthian or Brucknerian heights; interestingly, though, no one would ever call Keats or Chopin sentimental.

The next, surely inevitable, question is the embarrassing one. Isn't all this densely stratified, no-holes-for-the-critical-probe surface not at least arguably and please don't think this is my reading of it, quite a lot like New Age? Harold?

"A lot of people ask that."

Which, you'll admit, is not an answer.

"When Lovely Thunder came out I had to make a kind of statement disassociating it from New Age, which as I see it is a music without form or resistance." Which is.

What Budd is trying to do is demonstrably more complex. New Age 'expression' follows the line of standardised ready-reckoner emotion; the space Budd works in – the widest space in the world – is that between performer and audience. It's here that his obsession with jazz comes in; though like Michael Nyman, he's a composer who needs his structures and isn't entirely at ease in purely improvised settings, none the less improvisation is an important background element.

"When we were college students, we were listening to jazz, bebop, Charlie Parker, Max Roach, Thelonious Monk, those guys, and we were pretty indifferent to anyone who didn't. It was a long time later, though" – and well into the avant gardist days – "when one of my students played me some Pharoah Sanders. It's incredible, it's just this guy expressing something, himself, his life; it's intense and quite naked."

What it also incontrovertibly isn't is pretty, except in an episodic way. Though he's worked with jazz pieces – notably the wonderful gloss on "After The Rain" on Pavilion Of Dreams – and with jazz musicians like Marion Brown – who solos on "Bismallhi ‘Rrahmini ‘Rrahim" on the same album – his instincts are still those of the composer for whom the fleeting moments of performance, like that first improvisational run across the Synclavier, aren't ends in themselves as they might be to a jazzman, but steps towards the creation of some ideal code for feeling.

The goal, it seems, is something close to what is expressed in an unforgettable (if I've remembered it right) line in Billy Budd, when a sailor's voice, not stuttering Billy's, is described as a "chime ... the veritable unobstructed outcome of the innermost man". The strain of far West, near East mysticism isn't hard to find. The day before we met, he’d been to London's Whitechapel Gallery to look at the current exhibit, American Cy Twombly's remarkable easel-board paintings and palimpsests.

"The reaction to those has been very remarkable, very hostile. But what I feel about those pictures is what I feel about my music. If you don't grasp it in an instant, at that first seeing or hearing, then you won't ever grasp it. That's the level at which it works and if it doesn't, then it may be my fault or it may be the audience's, their presuppositions and prejudices getting in the way."

For all the dead end it seemed, everything he has done since 1970 has been a progressively more complex crystallisation from the simple sugar of that candy-apple chord. Taste.