When guitarist John Mooney first performed in Washington a few years back, he sang a brighter shade of the blues. He relied heavily on traditional sources for his lyrics, but with an assist from a bassist and a pianist, he often charged his songs with the exuberance of jug-band music. Back then, the good times rolled.

Now Mooney is performing alone; and though he still aims to please, he is concentrating more on being a musician than an entertainer. At the Door last night, he demonstrated his exceptional speed and sensitivity on slide guitar by using several different steel-bodied instruments, each producing a distinct and resonant tone. Sometimes the effect was lighthearted, as on "Fishin' Blues" and "Shortnin' Bread," tunes that immediately set toes a-tappin'. But more often it was the emotional sound of raw Delta blues, songs like Son House's "Levee Camp Moan" that commanded one's attention. Sung in a convincing full-blooded baritone, those songs were remarkably free of affectation or pretense.

The irrepressible Reverend Billy Wirtz was an ideal opening act. The pianist mixed risque' boogie-woogie numbers with robust rockers. He even managed to bring "heavy metal to Vegas" with his silly but wonderful cocktail piano renditions of "Jumpin' Jack Flash" and "Cocaine."