When people talk about the great Texas bluesmen, Buddy Ace's name doesn't come up nearly as often as it should. Ace was already a local sensation as a teenager; his first 45, on Don Robey's Houston-based Duke label, came when he was all of 16. In 1966, his "Nothing in This World Can hurt Me" propelled him into national R & B celebrity: he toured with the likes of Bobby "Blue" Bland and Johnny "Guitar" Watson and solidified his reputation as a powerful blues crooner who can ride the rhythm of a tune to extract maximum emotional heat. Since the mid-60s Ace's recording success has been sporadic--his last disc to reach the national R & B charts was "Hold On (to This Old Fool)" in 1967--but his power as a vocalist is undiminished. His velvety vibrato shows Bland's influence, but he's also got the ability to ascend from a sexy murmur to an agonized, sanctified scream. Ace puts on the kind of blues show we seldom see anymore--elegant, emotionally satisfying, and refreshingly adult. Tuesday through Thursday, 8 PM, Club Regal, New Regal Theater, 1645 E. 79th St.; 721-9230.