What got into John Mayer? Sometime after the release of his 2003 sophomore album, Heavier Things, a perfectly pleasant affair that expanded on the dreamy, mellow adult pop of his breakthrough hit, "Your Body Is a Wonderland," he decided that he just didn't want to follow that direction anymore.

He started penning a monthly column for Esquire magazine, within which he hinted that his musical tastes were far broader than his recordings suggested, and then he started cameoing all over the place, appearing on albums by Buddy Guy, Herbie Hancock, B.B.

King, Eric Clapton, and John Scofield -- heavy hitters one and all, yet none of them seemed to have much to do with Mayer's music, at least on the surface.

These veterans recognized something within Mayer's playing, but more importantly, he realized that he needed to push himself further and decided to expand his horizons by seizing the opportunity to play with these masters and then incorporating what he learned into his own music.

He toured as a power trio with studio pros Steve Jordan and Pino Palladino and recorded the live album Try! while on the road.

There are no two ways about it: anybody who dismissed Mayer as a lite Dave Matthews wannabe based on his first two records will be forced to reassess him on the basis of this excellent record.

While he still has some vocal tics that bring to mind Matthews and certainly shares an affection for lengthy live jams, Mayer has developed serious chops that transcend boilerplate jam band rock, where the groove and feel is more important than what's played.

Here, Mayer is pushed by Jordan and Palladino -- and he pays back the favor by giving them equal billing on the album's front cover, which is unusual for any pop/rock star of his popularity (the cover also marks the second Blue Note allusion in Mayer's oeuvre, which is surely not a coincidence) -- and he rises to the challenge with muscular playing that's his best playing on record.

Not just that, but there's a palpable grit to Try! -- and a sultry smoothness to the mellow numbers -- unheard on his previous studio albums.

That alone would make Try! not just noteworthy, but a step forward for Mayer.

But what makes it more remarkable is that Mayer takes an even greater risk by relying on new material for this album.

There are two older songs -- "Something's Missing" and the hit "Daughters," both from Heavier Things -- but the rest consists of covers of Jimi Hendrix and Ray Charles ("Wait Until Tomorrow" and "I Got a Woman," respectively) and new songs that showcase Mayer's earthier, blues-rock direction.

Although he sometimes dips into blues-rock clichés -- particularly on the slow-crawling "Out of My Mind" -- it's only on occasion (and when he does tread that familiar ground, he does so with conviction), and the songs overall are his strongest, most ambitious set of tunes yet.

And that's what's most impressive about Try! -- Mayer has expanded what he can do as a musician and a writer and in the process has definitively separated himself from the pack of sensitive, jammy modern singer/songwriters.

Based on this, he has more heart, soul, ambition, and chops than the rest of them combined.