Electric guitarists can spend years searching for tube-powered amplifiers that will give them the perfect tone.

Now many of them are on the hunt for the tubes themselves.

Long made obsolete in most consumer electronics by printed circuit boards, vacuum tubes are still used in guitar amps and hi-fi equipment. Aficionados say the tubes—just a few inches tall, with heated filaments that resemble a dimly glowing bulb—provide a warm, creamy tone unmatched by solid-state circuitry. 

“It’s something I don’t think you can actually put into words,” said Peter Frampton,  whose bestselling 1976 album “Frampton Comes Alive!” was a showcase for tube-amp-powered guitar solos. “Whatever you put through an amp with tubes is going to have extra warmth.”

Electric guitarists can spend years searching for tube-powered amplifiers that will give them the perfect tone.

Now many of them are on the hunt for the tubes themselves.

Long made obsolete in most consumer electronics by printed circuit boards, vacuum tubes are still used in guitar amps and hi-fi equipment. Aficionados say the tubes—just a few inches tall, with heated filaments that resemble a dimly glowing bulb—provide a warm, creamy tone unmatched by solid-state circuitry. 

“It’s something I don’t think you can actually put into words,” said Peter Frampton,  whose bestselling 1976 album “Frampton Comes Alive!” was a showcase for tube-amp-powered guitar solos. “Whatever you put through an amp with tubes is going to have extra warmth.”

As a prelude to its plan to return U.S. astronauts to the moon’s surface for the first time since 1972, the National Aeronautics and Space Administration has asked several space-robotics companies to design their own pod-like lunar landers to ferry scientific instruments and gear to the surface without a crew. At least two of these commercial entities also plan to send up art, though it’s unclear which one will be ready to launch first.

The lander with Mr. Koons’s art is pledged to hitch a ride aboard a Falcon 9 rocket provided by Elon Musk’s SpaceX, while Mr. Jafri’s project will fly on a Vulcan Centaur rocket designed by United Launch Alliance, a joint venture between Lockheed Martin and Boeing Co.

Jeff Koons is in a race to be the first man to display his art on the moon, an exhibit that could net him a fortune.

Mr. Koons, the world’s most-expensive living artist, is known for creating mirrored steel sculptures evoking balloon animals that have sold for as much as $91 million. Now, the artist has made an artwork he thinks can survive a 238,900-mile trip to the moon aboard a lunar lander slated to take off this year.

To succeed, he will need to rocket ahead of rivals including Sacha Jafri, a London-based painter who gained fame last month for creating the world’s largest painting and is now seeking to install his own art on the moon.

Jeff Koons is in a race to be the first man to display his art on the moon, an exhibit that could net him a fortune.

Mr. Koons, the world’s most-expensive living artist, is known for creating mirrored steel sculptures evoking balloon animals that have sold for as much as $91 million. Now, the artist has made an artwork he thinks can survive a 238,900-mile trip to the moon aboard a lunar lander slated to take off this year.

To succeed, he will need to rocket ahead of rivals including Sacha Jafri, a London-based painter who gained fame last month for creating the world’s largest painting and is now seeking to install his own art on the moon.

Rob Thomas, 50, is a Grammy-winning singer-songwriter, a solo artist and lead singer of Matchbox Twenty, which is planning an upcoming tour. He spoke with Marc Myers. 

When I look back at the low points in my childhood, I’m amazed I survived and emerged where I am now.

My mom, Mamie, married at age 14 to escape her abusive mother, Mattie. She had her first child at 16, divorced, remarried, had me at 21, and divorced again when I was 2 in the mid-1970s. 

We were all but doomed to a life of poverty. But to her credit, my mother did manage to give us a better life. 

After my mother’s divorce, we had to move into Mattie’s two-story house outside Lake City, S.C. It was attached to her general store. My mother, my sister, Missy, and I lived downstairs. Mattie sold liquor illegally stored in a secret space under the stairs.

Rob Thomas, 50, is a Grammy-winning singer-songwriter, a solo artist and lead singer of Matchbox Twenty, which is planning an upcoming tour. He spoke with Marc Myers. 

When I look back at the low points in my childhood, I’m amazed I survived and emerged where I am now.

My mom, Mamie, married at age 14 to escape her abusive mother, Mattie. She had her first child at 16, divorced, remarried, had me at 21, and divorced again when I was 2 in the mid-1970s. 

We were all but doomed to a life of poverty. But to her credit, my mother did manage to give us a better life. 

After my mother’s divorce, we had to move into Mattie’s two-story house outside Lake City, S.C. It was attached to her general store. My mother, my sister, Missy, and I lived downstairs. Mattie sold liquor illegally stored in a secret space under the stairs.

Two letters all over social media started as a jolly greeting among cryptocurrency fans and went on to inspire a new virtual currency, real-life tattoos and, naturally, online squabbles.

The catchphrase “gm”—or, to put it the old-fashioned way, good morning—is increasingly popping up on Twitter, Telegram and Discord channels, often alongside images of surf, sun-dappled flowers and sunsets.

The abbreviation is more than just a pleasantry for people who embrace blockchain, the technology underpinning virtual currencies like bitcoin. Blockchain enthusiasts are using it to signal that they are early to a technology whose future they believe is bright. 

Two letters all over social media started as a jolly greeting among cryptocurrency fans and went on to inspire a new virtual currency, real-life tattoos and, naturally, online squabbles.

The catchphrase “gm”—or, to put it the old-fashioned way, good morning—is increasingly popping up on Twitter, Telegram and Discord channels, often alongside images of surf, sun-dappled flowers and sunsets.

The abbreviation is more than just a pleasantry for people who embrace blockchain, the technology underpinning virtual currencies like bitcoin. Blockchain enthusiasts are using it to signal that they are early to a technology whose future they believe is bright. 

TOKYO—The Tokyo Stock Exchange inaugurated its new top-tier Prime section on Monday, and all the familiar names were present, Toyota, Sony, Honda and the like.

And then there was Econach Holdings Co. , which has 13 full-time employees and hasn’t paid a dividend since 1969. The company owns Thermae-yu, a bath and spa in a Tokyo red-light district that features a massage parlor, a pub and all-night service.

It is no insult to say that Econach operates at some distance from the stock exchange’s aim that Prime companies “center their business on constructive dialogue with global investors” and serve as “investment instruments for many institutional investors.” The bathhouse’s top-tier ranking can be chalked up, in part, to Japan’s respect for the venerable, an area in which Econach excels. Its history dates to 1926.