Santogold, Liquid Room, Edinburgh<br/>Martha Reeves and the Vandellas, Concorde 2. Brighton

Santogold may make perfect tunes for marketing cars and trainers, but she will never wow a crowd like Martha Reeves

Santogold is, like the enigmatic Max Vail in Nik Cohn's 20th Century Dreams, one of those people who just know people, and who gavotte through life's dancefloor via a series of fortuitous acquaintances, propelled by the self-perpetuating force of their own networking skills.

Santi White, as she is also known, a privately-educated thirtysomething from Philly, has been biding her time in little-heard punk bands until recently, when all those hard-won contacts fell into place. Names? How about Mark Ronson (she sang The Jam's "Pretty Green" on Version). Or super-producer Diplo, or, in turn, his star protégé MIA. She's also mates with Bjork, she's guested with GZA, written for Ashlee Simpson and Lily Allen, and snagged the support slot on the Coldplay tour.

Meanwhile, her self-titled debut album has been out since January, and already its songs have been used to sell shampoo, beer and cars, and to soundtrack computer games. For her most lucrative coup – or sellout – of all, she's recorded a song with Pharrell Williams and Julian Casablancas for the once counter-culturally cool, but now Nike-owned, trainer company Converse. Is she sitting on a folder of the juiciest blackmail photos on the planet? Or could it be pure, uncut charisma?

She has plenty of the latter. Flanked by dancers in musketeer frills and perma-shades and backed by a band in blue dickie bows, she bounds on stage in a flat leather cap, gold hoop earrings big enough to have shod a shire pony and a jumpsuit which is, if not a full blown riot of colour, then at least a major civil disobedience, and oozes nonchalance and star quality.

When you have a voice that could effortlessly walk into any Trojan compilation of late '70s lovers' rock and demand top billing, it's hard not to be confident. Indeed, for much of her heavily front-loaded and very curt set (eight songs, one encore, and I overhear the bar manager saying "that was one of the worst nights ever") she's essentially straightforward Jamaican soundsystem MC, and could be taken as some sort of cunning ruse to get white indie kids to listen to reggae music.

Her finest moment so far falls into this category. "Shove It", inexplicably still not a single, is an echo-laden skank which responds to the empty words of government, paying lip-service to ameliorating conditions for the poor, with a slap in the mouth: "We think you're a joke/Shove your 'hope' where it don't shine..." In an odd way it reminds me of "Joyriders", the social worker-taunting song by Pulp: "Hey you, you in the Jesus sandals/Wouldn't you like to come over and watch some vandals/ Smashing up someone's home?"

At the other end of her range, there's the taut, New Wavey "L.E.S. Artistes", which lampoons the pretentiousness of Lower East Side scene. Or "Creator", which, with its rumbling white-horses-in-the-surf drums, sounds like it could be advertising Guinness. Give it six months. Santogold live is, in contrast with her sometimes sombre album, a potent party-startin' turn, the perfect warm-up act.

She'll never know it, but Martha Reeves saved my life. There are some kids who, disenfranchised by the present, abscond in their minds to the past. In my case, inspired by a desire to seek out the source material of my early '80s Soulcialist heroes, my escape route was Tamla Motown. And one song, recorded before I was born, soundtracked my teenage bedroom more than any other, the autochange arm of the inherited Alba stereo set to repeat. "(Love Is Like A) Heat Wave" by Martha & The Vandellas may, when you break it down, be merely an early Holland-Dozier-Holland love song from the Motown conveyor belt, but something in the timbres and resonances of its vinyl grooves expressed an unquenchable yearning, a belief in the possibility of a better place and time.

It's an emotional moment, then, seeing Martha Reeves in the flesh, dressed up in tinsel, a tambourine at her hip, and aided by her sister Lois, a Vandella since '68, and baby sister Delphine who, touchingly, carries a lace hankie and dabs her eyes when it all gets a bit too much. When they sing "Come And Get These Memories", everyone has their own, different to, but not dissimilar from, mine. Alabama-born, Detroit-raised Martha Reeves served her apprenticeship in The Del-Phis, local rivals of The Primettes (the proto-Supremes), before getting herself a job as secretary to A&R man Micky Stevenson in Motown's Hitsville USA headquarters. She bided her time until star singer Mary Wells didn't turn up for a session one day, and Martha and her Vandellas stepped in. The Vandellas rapidly eclipsed the Marvelettes as Motown's foremost girl group, and took off faster than The Supremes, to whose reedy Diana Ross, with whom she frequently feuded, Martha provided a more soulful and gutsy alternative. As 1964 turned to 1965, however, the Supremes pushed ahead, and Martha was left embittered, complaining of her unfair treatment.

By the late 1960s she'd suffered a breakdown, and the glory days were over. She recorded one solo album, Martha Reeves, but was forced to settle into life as a nostalgia act – and, more recently, running successfully for political office – while Ross went on to world superstardom.

But what a nostalgia act. At 67, Reeves has still got the pipes, whether it's belting out hits like "Nowhere To Run" and "Third Finger, Left Hand", the old blues standard "A Love Like Yours Don't Come Knockin' Every Day", or the inevitable climax of "Dancing In The Street". She's a charming and disarming character too, quipping to her drummer "You've got to slow down for me, I'm an old person", joking about the AARP (American Association of Retired Persons), and telling tales of touring with Dusty Springfield. But the cover of "What's Going On", in tribute to "my friend Marvin Gaye", isn't gratuitous namedropping: the Vandellas sang uncredited backing vocals on "Stubborn Kind Of Fellow" and "Can I Get A Witness" and, according to Supreme Mary Wilson, Reeves had a major crush on him. Before "Jimmy Mack", Martha jocularly asks us to look out for her vanished man, "still wearing that same old three-piece polyester suit, moccasins, three feathers in his hair, love beads, giving everyone peace signs... He's stuck in the '60s." And so, quite happily, are most of the crowd. Post-show, she's mobbed by middle-aged mods queuing for autographs. (Yes, me too. The Tamla Motown paper sleeve for my copy of "I'm Ready For Love".) Because, for some of us, whether ageing scooterists or former introspective daydreamers, Martha Reeves and The Vandellas ignited a flame that can never be extinguished. Burning, burning.