Sources close to the Cali MC tell us the reason Xan axed 5 upcoming shows -- mostly in Texas and the Midwest -- is to recharge after long hours in the studio recording a new album called, "Be Safe" ... a tribute album to Mac, who died in September.

We're told Xan's been working nonstop on it -- if he wasn't onstage somewhere, he was in the studio trying to perfect the project -- and, at this point, he just feels burnt out.

Instead of putting on half-ass concerts, our sources say Xan opted to rest up and then hit the ground running again in Colorado on Nov. 6. He's planning to reschedule the canceled shows, but anyone who wants a refund will get it.