When you take a look at the liner notes for the self-titled debut album by the Los Angeles quartet the Shelters and see that Tom Petty co-produced it, the sound makes perfect sense. Each song seems to be a mix of the styles Petty has drawn from for decades: There’s the Byrdsy jangle on “Fortune Teller,” the layered acoustic guitars on “Gold,” and the piston-pumping, late-’60s garage rock on “Rebel Heart.” But as it turns out, the band had created a lot of the songs on this album long before Petty got involved.

“We’ve been at it for almost four years in some form or another,” says singer/guitarist Josh Jove. “(Singer/guitarist) Chase Simpson and I were in a band together before this one, and that started a guitar interaction between Chase and me that created the whole idea for the Shelters. But it took us a long time to learn how to craft songs that we felt confident about; we’d been working on some of those songs for two years before the record came out.”

The band’s mixture of vintage styles caught Petty’s attention just after they started playing live a couple of years ago, but he kept a bit of distance at first. He gave them access to his home studio and largely left them alone for a while to see what they could come up with.

“A lot of bands don’t get the opportunity to spend that much time in the studio,” Jove says. “So for us to be able to go in there over a course of time to record songs as we finished them was great. Chase and I did a lot of the engineering, and we’re not engineers by nature, but we learned how to do it to get the sounds we liked. Being in a situation where we were able to turn the knobs ourselves and explore and be a little more experimental was really good, whereas in a recording studio it’s hard to get away with that. It influenced the record hugely that we weren’t in a formal studio setting.”

Petty gradually became more involved in the production as the band came up with songs and arrangements that fit his simple-but-stringent conditions. “We really had to earn the involvement we ended up with from Tom,” Jove says. “He wanted to make sure we could create songs that could turn his head and that he could go away humming, and songs that were tight. So about half the record we did on our own as far as production goes, then Tom started to take it a little more seriously once we had a handful of songs Tom he liked.”

The album ended up sounding like a delightful spin through the rock radio dial, blending airy vocal harmonies with a tight-but-loose rhythm section, and layers of crisply strummed guitars. “The arrangements were fine-tuned up until the moment the record was finished, because we didn’t want to record anything that wasn’t perfect,” Jove says. “We didn’t want to have anything less than great out there. What we put out on the record is what we decided as a group that we’re most proud of and confident about.”

So what’s Tom Petty like as a producer, and how do you not freak out about working with a bona fide American rock ‘n’ roll legend? “Writing songs and having them judged by one of the greatest songwriters of all time is definitely intimidating,” Jove says. “But he’s such an easy-going person that interacting with him is not intimidating at all. Once you’re in the moment, he’s so cool and collected that you never really feel intimidated by him. But his presence is undeniable.”

In fact, once they adjusted to that presence, Petty functioned more as a facilitator/collaborator than a hands-on producer. “He liked letting us loose to do our own thing, but he was hands on when the song calls for it,” Jove says. If we went down a rabbit hole, he’d stop us and say, ‘That’s not going to turn into anything,’ or ‘Maybe you need to rethink this part.’ He’s very into crafting songs. He wasn’t going to lead us astray.”

Whatever they came up with, it worked, because the band’s career has been on an upward curve since the album came out last June. They’re currently playing an extensive tour with Band of Horses, they appeared on the Late Show with Stephen Colbert to play “Rebel Heart,” and they’ve received critical raves from Billboard, Rolling Stone, and others.

“When we play shows now, we’re seeing a reaction to certain songs,” Jove says. “People are singing along, which is the clearest way to tell if there’s been some kind of progress. It’s super encouraging to see people know the music instead of being some new band they’ve never heard.”