The old inventor peered admiringly at the display of vacuum tubes, the unwieldy predecessors of transistors and microchips powering nearby displays of modern-day televisions and stereos.
"Some people still insist they get a better sound from vacuum tubes, but they stopped making them," said Marvin Camras, 74, who, like the old-fashioned tubes, seemed slightly out of place amid the blaring sound and flashing images of the Consumer Electronics show here recently.
Camras, a humble, bespectacled figure, was circulating anonymously around the displays, unknown to the thousands of salespeople hawking electronic equipment that represents mere refinements of devices Camras had invented.
Corporate giants such as International Business Machines Corp., Sony Corp., Minnesota Mining & Manufacturing Co. and General Electric Co. owe a good chunk of their fortunes to magnetic tape, tape recorders, videotape and computer disks invented by Camras.
"They tell me I'm responsible for $5 billion in sales annually," said Camras, in what could well be a modest estimate. But Camras himself has seen little of the profits because most of his inventions were not widely used until after their patents had expired and they became part of the public domain.
Who's Who in America says that Camras, who prefers to be called an engineer rather than an inventor, is responsible for developments in audio and videotape recording, stereo sound reproduction and motion picture sound.
The first of Camras' hundreds of patents was in the early 1940s for a device that accurately recorded his cousin's operatic singing on a spool of steel wire. The cousin, upon hearing the recording, decided against a musical career, but Camras' ambitions were encouraged, and he soon scored some notable successes.
During World War II, recordings of battle sounds made on Camras' device were blasted onto French beaches through giant speakers in an attempt by the Allies to divert waiting German forces before the D-Day invasion. The wire recorders were also used to record the cockpit conversations of the best training pilots and to teach sailors about submarine warfare.
Camras, who is a Chicago native, worked as an independent researcher at Armour Research Institute in Chicago, now the Illinois Institute of Technology, where he still teaches.
Camras frequently had to do battle with recording artists and phonograph companies, he said, because those people feared his devices would allow consumers to make copies of their music.
But in fact, his greatest invention--the metallic coating for tape on which magnetic pulses are recorded and then replayed as sound and, later, as pictures and computerized data--would allow people to do that and more.
Camras said that he happened on the idea for the now-ubiquitous personal stereo 30 years before Sony Corp. founder Akio Morita did.
"Mr. Morita probably would be embarrassed if he saw that picture of me listening on headphones to the first stereo recording ever made," Camras said. Camras said that at the time, he thought the device would never catch on because it would be seen as unsociable. His friend Morita, however, ignored that concern to market the phenomenally successful Walkman.
As he toured Sony's dazzling exhibition at the electronics show, Camras scrutinized the miniaturized videocassettes and camcorders, personal stereos and giant televisions. The tapered designs and sharper images of the newest TVs did not much impress Camras, but he was marveling at the video cameras' small size and the laser disks' clarity of sound.
"I guess the problem now is inventing the time to watch all these things," Camras said. "That's what's expensive."