For the past 20 years, A Traveling Jewish Theatre has conjured up the romantic ideal of a ragtag, bohemian troupe struggling to create experimental pieces for the stage.

Even its first permanent site, which opened to the public three years ago, doesn't exactly trigger an image of establishment. Located between the Mission District and Potrero Hill in San Francisco, the theater sits in the basement of a one-time factory now managed by a nonprofit artists' co-op.

But the ensemble, which has tripled its box-office receipts in four seasons, is trying to raise the curtain on a different future. This week it announced plans to wrap up a $750,000 fund-raising campaign over the next four months and complete major renovations to its playhouse.

"It will be one of the nicest small theaters in the Bay Area, and maybe in the country," said Jim Kleinmann, ATJT's managing director.

Construction has already begun. The work is expected to be done in time for the ensemble's 20th season, which starts in November.

Most noticeable to theatergoers will be a new entrance directly into the 2,400 square-foot space, as well as new seating for 85, air-conditioning and better access for the disabled. Most exciting for performers will be sound-proofing, a new stage and dressing rooms, and better lighting and sound equipment.

The troupe has already raised about $550,000 through private fund-raising. But it still needs $200,000, which is why it's now reaching out to the public.

Dan Cohn, ATJT's board president, said the ensemble's most ambitious fund-raising campaign deserves the community's support.

"A Traveling Jewish Theatre, for 20 years, has produced great work," Cohn said. "I think we've paid our dues."

Aside from the physical changes, the final transformation from transience to permanence has been a long time coming — too long — for its founders.

Non-stop touring lost its charm a while back for the performers, now in their 40s, 50s and 60s.

"Of course, it gets old," founding member Albert Greenberg said.

Greenberg joked that the new status could even lead to a different name — "A Sedentary Jewish Theatre."

More seriously, he added, the "traveling" element of the name "has always been about the imagination anyway."

That journey has covered immense ground: black-Jewish relations, the demise of Yiddish, aging lesbians, infertility, Russian revolutionaries, exorcism, father-son relations, intermarriage and Mideast politics.

The 1998-99 season will feature the premiere of "Diamonds in the Dark: An Exploration of Yiddish Poetry" and "Schtick! A Queer Play on Yiddish Vaudeville," as well as the revival of "Heart of the World" and "Berlin, Jerusalem and the Moon."

Although ATJT has owned its site since 1994, the ensemble bought it for a mere $20,000. Once it pours hundreds of thousands of donated dollars into the space, ATJT will assume a sense of ownership and permanence it has never known before.

Greenberg, who is overseeing the renovations, doesn't see the new status as limiting or confining. Instead, he said, it sets the stage for artistic expansion.

"It opens up our vision to things we have wanted to do for years."

The ensemble members, who also include Naomi Newman, Corey Fischer and Helen Stoltzfus, want to spend more of their time writing and directing. Starting this fall, they will begin hiring a greater number of professional actors to take their place onstage.

The ensemble will continue to do some touring, though on a much more limited basis.

ATJT also will expand its training of young actors — a program that began last summer and was put on hold during the renovations. The ensemble will eventually create a year-round apprenticeship.

"We want the work to continue to survive," Kleinmann said.

In addition, ATJT will expand its salon series for Jewish poetry, short stories and music. The theater will begin to offer films and lectures. And it will expose more Jewish students to drama by taking the productions into day schools and synagogues.

Perhaps most critical to the ensemble's success, the renovations and a 20th-anniversary marketing campaign are expected to attract more theatergoers.

Since ATJT moved into its space at the former factory in 1995, its audience has grown substantially.

In the 1994-95 season, ATJT gave 32 performances, attracted 2,560 theatergoers and brought in $33,918 in ticket sales. In the 1997-98 season, those figures jumped to 98 performances, 6,309 viewers and $94,359 in sales.

The projections for the 1998-99 season are the most promising yet — 140 performances, 9,070 audience members and $140,400 in ticket sales.

"We still haven't reached our potential," Kleinmann said.

Greenberg doesn't believe the audience has grown because the theater's quality has improved or because Jews are more open to Jewish theater.

"It's because of the space," he said bluntly.

At the same time, Greenberg describes the theater as "pretty funky right now."

Ticket-holders currently enter the large industrial building's side door marked by a small ATJT sign. They head downstairs and walk 50 yards through a concrete hallway shared by other artists who live and work there.

Those with disabilities must go to the other end of the building and enter through a garage.

There has been no air circulation. Sometimes noise leaks in from surrounding work areas.

The stage is inherited and old. The seats were hauled from the Berkeley Richmond JCC's crawl space; they were left over from the defunct Pacific Jewish Theater.

"We have first-class content and first-class production in a second-class space," said Cohn, who also chairs the capital fund-raising campaign.

An attorney, Cohn acknowledged that even he "would have reservations about bringing a client or an older person to the space."

This fall, audiences will discover a well-lighted, glass canopy reminiscent of a Paris Metro station. The entrance will be at the building's front, next to Theater Artaud's entry, and will bring theatergoers directly into ATJT's space.

A new entrance is more than practical. When ATJT bought the space, it agreed to build a separate entrance.

Other renovations include a lift for disabled patrons, a new stage with more suspension and cushioning, new restrooms, and a box office, mezzanine and lobby.

The architect for the project is Freebairn-Smith & Crane.

Within a few years of completing the renovations, ATJT may have some cultural competition. The Jewish Museum San Francisco's new site will include an auditorium designed to showcase the arts.

But Greenberg said he isn't worried that the Bay Area will be oversaturated with artistic works.

"There are too many Godzillas playing at multiplexes — that's the problem," he said.

Instead, Greenberg said, ATJT and the museum will likely work together on occasion. At the same time, he dismisses any suggestion that the ensemble could have moved into the museum's new site.

"They couldn't accommodate our schedules," he said.

Apparently the established Jewish community agrees.

So far, donors to ATJT's campaign have included the Jack Langsam Fund of the Jewish Community Endowment Fund, the Walter and Elise Haas Fund, the Bernard Osher Jewish Philanthropies Foundation, the Fleishhacker Foundation and philanthropist Roselyne "Cissie" Swig.

To raise the remaining $200,000, the ensemble is sending an appeal to its mailing list. It is also offering incentives to donors, such as naming seats, the dressing room and the mezzanine.

For $150,000 or even a bit less — it's negotiable — a donor can name the entire theater.

While such fund-raising is blatantly establishment, Greenberg doesn't believe ATJT's original vision or integrity has been lost.

"Twenty years ago, it was about doing one play. We didn't have a cultural manifesto," he said.

"It's still about what excites us artistically."