NEW YORK — Jonas is back, if only briefly. Anna is here, in full diva mode. The seemingly unstoppable Placido marks his 50th anniversary. And the "Ring" contraption returns — maybe for the last time — with a promise of greater reliability and fewer "clunks and clicks."

These attractions and more are on tap as the Metropolitan Opera opens its 134th season on September 24 with a new production of Saint-Saens' "Samson et Dalila" starring Elina Garanca and Roberto Alagna. It winds up 212 performances later on May 11, with the final installment of Wagner's four-part "Der Ring des Nibelungen," starring Christine Goerke as Bruennhilde.

This will be the last season before the company launches Sunday matinee performances, a move aimed at boosting sagging box-office revenues.

Besides "Samson," there are new productions of Verdi's "La Traviata," Cilea's "Adriana Lecouvreur" and a recent work, Nico Muhly's "Marnie," adapted from the book that inspired the Alfred Hitchcock film. But many opera lovers are just as enthused about the wealth of intriguing revivals.

"It's one of the strongest seasons in years, featuring important, starry revivals of some of the operas I love best," said James Jorden, editor and publisher of the online opera magazine "parterre box." He cited in particular a revival of Debussy's "Pelleas et Melisande," conducted by the Met's new music director, Yannick Nezet-Seguin.

Other major revivals include Poulenc's "Dialogues des Carmelites," again conducted by Nezet-Seguin; Puccini's three one-acts, "Il Trittico," commemorating the 100th anniversary of its Met world premiere; and Verdi's "Otello," led by L.A. Philharmonic maestro Gustavo Dudamel in his Met debut.

A few of the highlights:

—The elusive Jonas Kaufmann, the most acclaimed tenor in the world today, jets in midway through the run of Puccini's "La Fanciulla del West" to sing four performances — including an HD broadcast — as Dick Johnson, the bandit with a heart of gold. Kaufmann has been absent from the Met since 2014.

—Anna Netrebko, the Russian soprano who has been a mainstay at the Met since her 2002 debut, has moved from light lyric roles into heavier repertory, scoring huge successes as Verdi's Lady Macbeth and Puccini's Tosca. Now she's taking on the touchstone of spinto soprano roles, Verdi's "Aida." The Met's general manager, Peter Gelb, heard her debut in the role in Salzburg, Austria, and said he was "not surprisingly blown away. ... In my opinion she's the best Aida since Leontyne Price." Netrebko will also headline the new "Lecouvreur," a verismo chestnut that's a favorite of prima donnas with a flair for melodrama.

—Placido Domingo, the 77-year-old tenor-turned-baritone, is, as Gelb noted, "somewhat obsessed with his various milestone achievements, as he deserves to be." Having just sung the 150th role of his career, in Salzburg, he celebrates his Met anniversary with a flurry of appearances: seven in Puccini's "Gianni Schicchi" and five in "La Traviata." He'll also conduct "Aida" three times and reign as guest of honor at a black-tie dinner dance on the Met stage (tickets start at $2,500).

—Finally, and most controversially, the $16 million, 45-ton "Ring" set conceived by Canadian director Robert Lepage, consisting of 24 giant aluminum planks arrayed on a central spine like a gigantic seesaw and supported by 26-foot-tall towers on either side of the stage. Through use of projections, the set created some spectacular visual effects, but it also was plagued by safety, reliability and noise issues from its first appearance in 2010.

The apparatus has now undergone a complete overhaul, much of it carried out over four months in an old train depot in Middletown, New York, under the guidance of Jeffrey Mace, the Met's director of production operations. Lepage himself is not returning for the revival.

Mace said the computer running the original set was "a stand-alone system that just controlled the machine" and a lot of the breakdowns stemmed from lack of integration with the Met's own computers. He said the systems are now linked, allowing operators to "diagnose and react much more quickly to bugs and problems."

As for noise, Mace identified two separate problems: first were the "clunks ... deep low-frequency sounds emitting from the towers" when "large steel elements were crashing into other large steel elements." Mace said his crews adjusted the connections between towers and planks to "eliminate as much freedom of motion as possible but not too much."

Then there were the "clicks," which Mace said came from a loosening of the nuts-and-bolts connections between sections of the seesaw itself. To keep these joints sufficiently tight, his engineers developed a "custom-made nut-tightening hydraulic wrench."

How successful has the effort been? "The clunks are gone," Mace said in an interview last month. "We're still working on the clicks."

Gelb estimated the cost of all this work at "several million dollars," though some of that was capital expenditure for technical improvements to be used in other productions.

Many question whether the effort was worth it. "I'm not sure there's a single person who is looking forward to seeing the Lepage production again," said musicologist Micaela Baranello. "It's the Met's white elephant."

Nevertheless, this season's revival has been selling well. And whatever the audience response, it may be the last opportunity to see the set in action.

"We'll see how it goes this time," Gelb said. "I think the jury is out as to whether this will ever play here again." He said Nezet-Seguin will surely want to put his imprint on his own production at some point: "Every music director wants to make his mark with his own 'Ring.'"