Sometimes great ingredients can make a pretty mediocre dish. Tom Petty and the Heartbreakers recorded seven gritty, powerful, electric-blues cuts for 'Kiss My Amps Live' but when played one after the other the album loses focus.

In small doses Petty's blues vocals sound inspired. His lyrics are saturated in emotion, often painful sometimes not. But he never really varies his delivery and by the time one gets to the chorus of 'Running Man's Bible' he sounds more Robert Dylan than Robert Johnson, that is, whiny instead of scarred.

Six of the seven songs were released previously on 2010's 'Mojo,' an album Petty recorded because the band finally felt they had the experience to pull it off.

Very little is added to these live renditions as they recorded each song nearly live in the first place.

No one will accuse Petty of copying blues greats like Muddy Waters and Howlin' Wolf; if anything he sounds like The Black Keys' lead singer Dan Auerbach.

(Editor's note: I respectfully disagree with this review. I'm putting my note here so Billy gets the last word, but there's a looseness and energy to these performances that was missing from the very good but overly polished 'Mojo,' and Mike Campbell runs wild throughout. This sounds like a re-invigorated band.)

The swampy 'Sweet William' is a highlight as is the delta blues inspired 'Jefferson Jericho Blues.' The effect of having a live amphitheater audience is lost by then, however, as there are few moments of impulsive interaction or audience explosion. We're only reminded that this is indeed a live album at the beginning and end of each track.

All this said, the Heartbreakers are on fire from start to finish on 'Kiss My Amps (Live).' Campbell shows his muscle, at times (perhaps unintentionally) pulling riffs from guitarists like Jimmy Page; four-and-a-half minutes into 'First Flash of Freedom' it sounds certain the band is set to go into 'How Many More Times.' It's as much of a showcase for their individual talent as it is a chance to reconnect with America's roots. For a live album though, one hopes for more surprises.