Young Girl With the Blues : * Music: Sue Foley, a 23-year-old from Ottawa, is earning raves for her riffs. She performs tonight at the Belly Up.

Over the years, the demo tape--usually a low-budget recording of a musician’s work--has become the unofficial unit of currency in the music business. Thousands of aspirants send them to record labels, artist managers, producers, concert promoters, club owners, and even critics, in the hope of negotiating a taste of the spotlight. Many demos end up in the waste heap--some before they’re heard--and the vast majority are not even acknowledged.

It is significant then, that, when Ottawa, Canada-bred blues guitarist-vocalist Sue Foley sent a demo to Clifford Antone in 1990, the owner of the well-known Texas nightclub and record label bearing his name was so impressed, he immediately sent her an airline ticket to Austin. Antone’s Records had been looking to groom a talented unknown with a genuine feel for the blues, and, apparently, Foley fit the M.O.

Two years later, Antone’s is poised to release Foley’s debut album, “Young Girl Blues.” Meanwhile, the 23-year-old pretender to the blues-queen crown is on the road earning raves with her gift for riffs. Foley will perform tonight at the Belly Up Tavern in a traveling show called “The Antone’s Women Texas R&B; Revue.” Others on the bill include singer-bassist Angela Strehli (a co-founder of the Antone’s label); honey-and-gravel-voiced Lou Ann Barton; veteran vocalist-guitarist Barbara Lynn; R&B; singer-songwriter Toni Price; and R&B; vocalist Miss Lavelle White.

In recent years, women instrumentalists have made great progress in other genres, but when it comes to the blues, most settle into the traditional female role of vocalist, even if they are capable of accompanying themselves. Foley challenges that stereotype, but there was a time when she might have conformed to it.

“There always was music in the house when I was growing up, and my dad, who plays Celtic music, had me singing from the time I was just a little girl. So, singing would have been a natural thing to do,” Foley said in a soft, slow voice earlier this week. She was calling from the Austin Motel. She plans to settle in Austin when she returns from a lengthy tour that will end in early summer.

“But dad and my three brothers all play guitar, so in a way it’s the family instrument,” Foley added. “When I was 13, my mom and I moved to Edmonton. I got bored pretty fast, and since I already felt that anything having to do with music was about the hippest thing imaginable, I asked my dad to send me a guitar. I’d never played one before, so I just plowed away at it.”

At the time, Foley was enthralled by the Rolling Stones, who, indirectly, lured her to her current wellspring--the music of the great blues pioneers.

“Because of my older sister, I heard the Stones’ records around the house practically from the time I was born,” Foley recalled. “I developed a real soft spot for them. But one day, I was reading about the Stones’ influences and I realized they were just copping the blues, you know? So, I tried to find records by Muddy Waters, Jimmy Reed, Slim Harpo--anyone who was mentioned in this article.”

Once Foley discovered those artists, she turned her back on the Stones and other rock ‘n’ rollers and became, in her words, “a teen-age blues snob.” Foley and a friend were just entering this phase together when they heard that James Cotton was coming to Ottawa.

“I was 15, and I’d been to concerts before, but I snuck into the James Cotton show and I was impressed that these normal-looking guys were really putting out on stage and reaching people,” Foley said. “I suppose I wanted to be gotten, and they got me. The music seemed so human, accessible, and down-to-earth, and it made me feel special. I went up and talked to the guitar player and the other musicians--something I’d never thought of doing before. I went home just elated and feeling real alive.”

Foley sequestered herself with her growing collection of blues albums and immersed herself in blues-guitar methodology. It was a lengthy process of developing a guitar voice worthy of public performance.

“It was a struggle for a long time, gaining confidence that I could jam with other musicians and stuff,” she remembered. “But I’m happy with where I am right now. There’s always more, you know. In fact, I’m practicing right this minute. But I’m pretty confident about my playing.”

That confidence is evident on “Young Girl Blues,” an album that mixes originals with covers of tunes by the likes of Earl Hooker and Ike Turner. While finger-speed might be an important prerequisite for playing certain rock variants, feeling, expressive breadth, and intensity are paramount for a blues guitarist. Foley handles the blues-guitar vocabulary with the fluency of a player twice her age.

Listen to Foley singing and fret-ripping through her own “Walkin’ Home”--shifting tonal gears, modifying her attack, bending the tempo, stoking the emotional furnace--and her work seems a musical love-child of Bonnie Raitt and Stevie Ray Vaughan. Appropriately, “Young Girl Blues” opens with “Queen Bee,” Memphis Minnie’s feminization of James Moore’s randy classic, “I’m a King Bee.” The song could be the ascendant Foley’s anthem, and it also provides a retroactive link with the Stones, who recorded Moore’s song on their first album. That’s a connection Foley no longer avoids.

“I’m coming out of my blues-snob period,” she stated with a laugh. “I just bought a new copy of (the Stones album) ‘Sticky Fingers,’ and I’m getting into that again. Listening to them after all this time, I realize the Stones were real funky and heavy; they laid down some good grooves and wrote some great songs.

“I want to write like that, but it’s hard,” Foley continued. “I worked on my guitar-playing first, then worked on my singing, and now, learning how to write songs is like learning a third instrument. I’m using a different part of my brain, and it’s difficult. But I’m just going to keep plugging away.”

* “The Antone’s Women Texas R&B; Revue”--featuring Sue Foley, Angela Strehli, Lou Ann Barton, Barbara Lynn, Toni Price and Miss Lavelle White--will be presented at 8:30 p.m. today at the Belly Up Tavern, 143 South Cedros Ave., Solana Beach. Tickets are $10 through TicketMaster (278-TIXS) or at the door. For more information, call 481-8140.