Leave it to the perverse old contrarian, who is about to turn 63, to throw us another curveball with his current tour, which includes sold-out shows at four progressively more intimate Chicago venues this weekend. (His local stand starts with Friday's concert at the Aragon Ballroom, continues with Saturday's at the Riviera Theatre, and concludes with Sunday's at the Vic Theatre and Monday's at the Park West.)

Dylan has spent the last decade building one of the best guitar bands in rock history, a group that is arguably as good as (if not better than) the vaunted Band. But the twist on this leg of his never-ending tour is that he's dropped his own ax and moved behind an electronic keyboard, which he isn't particularly adept at playing and which was barely audible in the usual muddy mix of the Aragon.

To be sure, Friday's show did not lack for six-string firepower. The core of Dylan's current band remains longtime sidekicks Tony Garnier on bass and Larry Campbell on guitar and pedal steel. It adds Freddy Koella on second guitar, and some of the best moments of the evening -- an angry version of "It's Alright, Ma (I'm Only Bleeding)" and a rollicking "Highway 61 Revisited" among them -- featured some fiery and inspired interplay between the two guitarists, who traded off on bluesy slide.

But Dylan has been much looser -- if not downright fun and groovy -- when he's been playing a third electric guitar, goading the musicians to greater heights as he weaved his parts in between those of Campbell and the now missing-in-action Charlie Sexton.

When he occasionally ventured out from behind his keyboard at the Aragon to play harmonica at center stage, Dylan seemed stiff and awkward, and the band followed suit, much less in his control than it has been in recent years.

Ironically, at the same time that the legendary singer and songwriter has ratcheted down the guitar pyrotechnics, he's upped the percussion assault. About half of Dylan's 90-minute set proper featured two drummers, George Recile and Richie Hayward, who did their best to bash away at whatever finesse remained in songs such as "Most Likely You Go Your Way (And I'll Go Mine)," "Cry A While" (which evoked two speeding trains colliding) and the usually sublime (but not this time) "It's All Over Now, Baby Blue."

With all due respect to the Allman Brothers -- and much, much less to the Grateful Dead -- I will state emphatically that there has never been a case in rock history where two drummers have been better than one. Eight limbs flailing are four more than are needed, and in any event, I thought Dylan got over his brief flirtation with the Baby Dead/jam-band crowd quite some time ago.

The best moments of the evening were the most subtle: The band pared down to one drummer for a beautiful rendition of "The Lonesome Death of Hattie Carroll" and a transcendent and mostly acoustic "Girl of the North Country." Unfortunately, high points such as these were in short supply.

As always, though, ol' Bob gave us something to think about, above and beyond the motives behind his devilish bouts of musical perversity. As the most significant issues affecting America's decision this coming November are overshadowed by such monumentally trivial distractions as the controversy over Janet Jackson's breast and the unabashed outpouring of prejudice about gay marriage, the central couplets of "It's Alright, Ma (I'm Only Bleeding)" seemed more poignant than ever:

"While preachers preach of evil fates / Teachers teach that knowledge waits / Can lead to hundred-dollar plates / Goodness hides behind its gates / But even the president of the United States / Sometimes must have / To stand naked."