They were still pressing 78 rpm records in the late 1940s when a Long Islander named Allen B. Jacobs took an office on Broadway, in what was then the heart of Manhattan's music business.

Jacobs' new on-the-cheap label, Tikva Records, would eventually be pressing 12-inch LPs, just one change transforming the recording industry. But the changes that interested Jacobs were the ones he captured on vinyl, no matter what size.

He started a record label - its name is Hebrew for "hope" and is also the name of Israel's national anthem, Hatikva, or "the hope" - that thrived on change and representing it, and then, when the change had become the status quo, died out. Now, the music Tikva sold has been rediscovered (rediscovered more than "found," as it was never really lost; Tikva records have sat all along in basements, attics, and bins at vinyl trading posts).

The music, though, had been largely forgotten until now, with the release of a new CD containing 20 selections from Tikva artists. The disc, on sale nationwide, is the work of the Idelsohn Society, a nonprofit founded five years ago by "four record-collecting Dumpster divers committed to rescuing Jewish vinyl from the thrift shops and flea markets across the country," as they wrote in a liner-note booklet accompanying the handsomely packaged CD. The eclectic songs run from early rock arrangements to klezmer, jazz, folk, cantorial, Yiddish, and nightclub-type novelties.

Tikva's music was recorded in the postwar years as American Jews were in major transition, becoming a part of the mainstream. Israel was then more than a concept, suburbs were filling out, and huge new synagogues would be a part of them. Yiddish theater was in rapid decline, but not performances by Jews scattered around the world, with many different takes on what constituted Jewish music in an age where their work would be more accessible.

Tikva records provided that as the only Jewish label devoted to all genres. One of its albums was a compilation, Jewish-American Songs for the Jet Set, a suggestion that listeners and performers were getting around and expanding their perception of themselves and their world. The new CD is a takeoff on that theme, called Songs for the Jewish-American Jet Set.

After 168 releases, Tikva records went out of business in the mid-'70s, and Jacobs died in obscurity, according to the society's research. Although the recording masters were lost in a fire, the society, with help from Tikva fan Ron Orenstein, has tracked down much of the catalog, creating the compilation from tracks on records.

"You can hear all kinds of different sounds that reflect the transition," said Josh Kun, an associate professor of popular music and culture at the University of Southern California's Annenberg School in Los Angeles.

Kun, an Idelsohn founder, said, "These records give us a window into Jewish American taste and preference. You can hear songs that reflect rock, classic, Hasidic, songs about Israel, Yemenite music, the international folk music scene centered in New York in the '60s, and on and on." The CD, he said, "has a kind of diasporic scope - these are songs connected to New Jersey, Long Island, Tel Aviv, and Jews on the move."

That mix is still in play: On Friday night, visitors at the Philadelphia Museum of Art's weekly jazz series were listening to klezmer music with a Latin bent. "I sang in about 12 or 14 languages" that extended to Japanese, said Avram Grobard, a Tikva artist whose jazzy rendition of the usually quiet "Orcha Bamidbar" ("Desert Caravan") is on the CD, and who owned El Avram, a club that thrived in New York's Sheridan Square for 15 years, until 1982.

Grobard is a native Israeli trained as paratrooper in the Israeli air force; his club mirrored the musical energy of the Tikva years. "When Jews started coming in from Russia, from the airplane the entertainers would come to my club to get a job."

Hoping the CD spurs more interest, the Idelsohn Society has opened a December-only pop-up Jewish record store in San Francisco's Mission District with free events and musical performances through the month, including all eight nights of Hanukkah.

"We try to find the stories we think we can tell in a new and exciting way," Kun said, "in order to excite new interest in the past."

To hear Bernie Knee's "Orthodox, Conservative, or Reformed" and Avram Grobard's "Orcha Bamidbar," go to www.philly.com/tikva.EndText

Contact staff writer Howard Shapiro at 215-854-5727, hshapiro@phillynews.com, or #philastage on Twitter.