Reception for The Avalanches' debut album Since I Left You – 16 whole years ago, as no one ever tires of pointing out – was divided between those who recognised it as the work of cross-stitching sampladelic genius it most certainly was and those who heard 'Frontier Psychiatrist', a red herring only linked to the rest of the album by thematic horse neighs, and decided, well, one Bentley Rhythm Ace was probably enough. The former have been justified by sheer weight of anticipation for Wildflower. There's no palpable sense anyone's holding out for a new Wiseguys album.

Still, you've got to wonder if Melbourne's premier record-crate archaeologists have anything more to offer this far down the line, whatever the tapes and tapes of material they may have accrued during that long, long gap. For those who care about such things, is a follow-up even relevant now?

But for insubstantial, if-you-say-so appearances from Father John Misty and Tame Impala's Kevin Parker, and more solid guest spots from Danny Brown and Toro y Moi, it's tempting to imagine Wildflower was recorded five minutes after The Avalanches came off tour in 2002 and that they really have spent the last decade-and-a-half clearing samples. There's nothing particularly 'now' about it. Either they've been cocooned away in some netherworld where post-big beat's still a thing (yes, 'Frankie Sinatra') or this is just the way it works; if they'd gone for something a bit more 2016, we'd be hearing it in 2030.

Not that Since I Left You necessarily screamed 2000, coming four years after DJ Shadow's Endtroducing, its only serious peer in the other-people's-records pantheon. It turned out timely though. Fellow crate-diggers Daft Punk were setting intriguing new parameters for dance music, their anything-goes ethos chiming with what Robbie Chater and Darren Seltmann were doing for The Avalanches down under, and mash-up culture was bastardising pop, for better or worse. If no new beats were coming, why not make a Frankenstein's monster out of some old ones?

Since I Left You was a beautiful monster, a seamless trip of ineffable joy (tinged with melancholy) that combined turntablist skill, pop nous and wild imagination. Hundreds of records, obscure and decidedly non-obscure (step forward Madonna's 'Holiday', one of the few famous samples to get the legal nod), were plundered for odds and sods that propelled the party to the stratosphere and then brought it back down again to an improbably gorgeous, Osmonds-fuelled coda. The unfamiliarity of most of the material probably eased the flow – there was a prototype album, the Gimix mixtape, incorporating whopping great chunks of Dylan's 'Like A Rolling Stone', Cyndi Lauper's 'Girls Just Wanna Have Fun' and The Smiths' 'The Boy With The Thorn In His Side', that sounded clever but jarring. All that stuff was best saved for their excellent radio mixes at the time, for Triple J, KCRW, Radio 1's Breezeblock and more.

Contemporary pop, house and hip-hop went into those mixes, but they were equally characterised by Since I Left You-like charity-bin finds and Beach Boys, lots of Beach Boys. Take away the Destiny's Child and DJ Zinc snippets and you were left with that sun-kissed, Super-8 world they'd created for themselves. Chater, Tony Di Blasi and James Dela Cruz – the Avalanches who've made it through the years, more or less – are still in that world now.

Wildflower is all sunshine and inexact nostalgia, the kind of territory The Go! Team occupy when they rein in the treble and whomping great beats, a place where you're a kid again, no fix on a daunting future. It starts gently, moving from a tried-and-tested found-sound intro to its first great discovery, a sample from 1959 urban field recording Street And Gangland Rhythms: Beats And Improvisations By Six Boys In Trouble, slapped on top of the Jackson 5-y swagger of The Honey Cone's 1971 US No.1 'Want Ads'. 'Because I'm Me' sets a state of euphoria that can't quite be washed away by the awkward 'Frankie Sinatra' before the delirious disco-funk of the Bee Gees-sampling 'Subways' reboots a groove that's sustained through its kid brother 'Going Home' and into Toro y Moi's guest slot on the dreamy, toybox electronica of 'If I Was A Folkstar'. It's not quite Since I Left You's four-song build into the explosive 'A Different Feeling', but there's a sense of a target being hit when Mercury Rev's Jonathan Donahue, such a natural fit here, launches into the psychedelic, twinkling pop of 'Colours'. This is where we've been heading. Wildflower's over the rainbow and it's staying there.

The mood's constant throughout the dense forest of samples, but featured vocalists enable some kind of separation between tracks that wasn't there on Wildflower's predecessor. 'Zap!' is a lush dream sequence jolted awake by TV and radio samples that segue into the incredibly catchy, cereal-chomping 'The Noisy Eater', a Biz Markie-fronted tribute to The Beach Boys' 'Vege-Tables' that finds its own way of bringing Paul McCartney on board. This time it's a propulsive snatch of a kids' choir singing 'Come Together', sanctioned by McCartney, who also lets The Avalanches use 'Uncle Albert' for the woozy 'Livin Underwater (Is Somethin Wild)'. Their pulling power's really beefed up in the last decade or so. Donahue's all over the place, apparently playing bow saw on the title track interlude and the heavenly shuffle of 'Harmony', and taking lead again on the zoned-out baroque of 'Kaleidoscopic Lovers'. Danny Brown's back again too, sharing the wonky funk of 'The Wozard Of Iz' with Dominique Young Unique (another might-have-been of the past few years) and a Shondells lift.

Perhaps the best collaboration's cooked up with Royal Trux's Jennifer Herrema, who brings rock'n'roll wreckage, "a pack of smokes and a can of spray paint" to 'Step Kids'' straggly campfire party, leading a ravaged singalong almost to the end. The actual closer is 'Saturday Night Inside Out', a warped but celebratory chug with cut-up vocals from Father John Misty and a poem from Silver Jews' David Berman. It's an update of 'A Cowboy Overflow Of The Heart', the Avalanches/Berman demo that snuck out four years ago, exciting rumours of an imminent (ha!) return, but it's also based on the very first post-Since I Left You demo Chater played to his then-bandmates all those moons ago.

Everything neatly parcelled up. Wildflower's more than that, though. Even if it could never feel like a childhood's worth of lovingly curated music, and even if the shock of the new's way out of its reach, it's still another out-of-its-time, forensically assembled wonder. Lightning rarely strikes twice, but 16 years slash those odds.