The opening notes of Nathaniel Rateliff and The Night Sweats’ “I Need Never Get Old” shear away decades. A simple, twangy guitar line is joined first by an insistent bass, then drums, then horns you can imagine swinging back and forth while playing a soul fanfare straight out of Memphis 1965, even though the band formed in Denver in 2013.

In the chorus, Rateliff sings like a classic soul shouter, and only the extreme reverb on the guitar says the song comes from R&B fans today and not an overlooked band from 50 years ago.

“I Need Never Get Old” is the lead track from Nathaniel Rateliff and The Night Sweats’ debut album from late this summer, and along with the high-energy single “S.O.B.,” it’s made the band one of the hits of the fall.

They appeared earlier this week on “The Late Show with Stephen Colbert,” and their sold-out show Sunday night at Tipitina’s was originally scheduled for Gasa Gasa but had to be moved to the bigger venue because of ticket demand.

They’re not the only retro R&B band playing this weekend.

St. Paul and the Broken Bones will headline the Emeril Lagasse Foundation’s Boudin, Bourbon & Beer in Champions Square on Friday night. The Birmingham, Alabama, band has played New Orleans a number of times since the 2014 release of its debut album, “Half the City,” most recently for The Landing festival in September.

Recently, The Rolling Stones’ Keith Richards identified the band as one of the few current bands he pays attention to, and said of singer Paul Janeway, “He’s a cat that can do an Otis Redding.”

Retro R&B is hot. Recently, Nicole Willis and The Soul Investigators released “Happiness in Every Style,” an album of tracks that sound like lost soul gems cut somewhere between 1968 and 1974. Sharon Jones and The Dap-Kings have been the retro R&B trailblazers since the release of their 2005 debut album, “Naturally,” and they followed the tradition of R&B Christmas recordings with their new “It’s a Holiday Soul Party.”

One common thread through these projects is an affection for a classic sound  —  one strong enough to make musicians want to find their place in it rather than wrestle it into modern times. “The stuff that was influencing me was the Bang sessions of Van Morrison and Sam & Dave and Otis Redding,” Nathaniel Rateliff told NPR.

“I really wanted to try to mix that Southern soul sound with a little bit of honky-tonk and what our Missouri roots are.”

Paul Janeway’s roots are similar. “My parents had me on a very strict diet of only gospel music, and the only outlier to that was a little bit of Sam Cooke, a little bit of Otis Redding,” he told Boston’s WGBH. “I always say some Marvin Gaye — pre-‘Let’s Get It On.’ I couldn’t listen to that.”

The bands wear their love of R&B proudly, but they’re not simply working from old templates.

Because the band members aren’t living in Memphis, Tennessee, in the mid-’60s or Detroit during Motown’s heyday, they’re making musical choices that the players on the albums never would have.

Gabe Roth, the bassist and bandleader for Sharon Jones and The Dap-Kings, acknowledges that they’ll pull a bass idea influenced by a New Orleans record and match that with a Motown drum part and lay some James Brown horns over it, creating a composite arrangement that sounds familiar but never would have happened back in the day.

“I don’t deny that our stuff has a real ’60s feel to a lot of it, but we don’t approach it as archaeologists,” he told New Orleans’ My Spilt Milk. “It’s very live music, and everybody’s playing with a lot of heart and soul.”

That heart and soul is clearly part of the sound’s appeal, and it’s no surprise that retro R&B’s growth tracks almost exactly with electronic dance music becoming the dominant musical sound in America.

At a time when pop, soul and hip-hop are touched by computers and electronic sounds, Nathaniel Rateliff and The Night Sweats, St. Paul and The Broken Bones, Sharon Jones and The Dap-Kings and Nicole Willis and The Soul Investigators are reconnecting with a very human, often gritty form of dance music.

Gabe Roth thinks The Dap-Kings’ music has more in common with punk rock than contemporary R&B.

“Most of that stuff is so produced and corny, and what we do has a rawness or a realness to it,” he said.

Rateliff acknowledges that he’s on trend at the moment, and even though he didn’t plan it that way, he hopes others pick up the retro R&B vibe as well.

“I’m excited that (R&B) is back,” he said. “I hope it lasts, and I hope other people have new and inventive ways to play soul and R&B that are real and a part of them.”