Every so often James MacDonald breaks into his own conversation to say a few words in the piping falsetto of Mickey Mouse. "Hello folks! Hi there!"

It clears his tubes, he says.

MacDonald is nearly 76, and he has been Mickey's voice since 1946, when Walt Disney was making "Mickey and the Beanstalk" and the animators were getting nervous because they needed the voice before they could draw--the sounds are broken down frame by frame so the character's mouth can be shaped correctly--and Disney, who had done Mickey himself from the beginning, was too busy.

So Walt called in Jimmy. After all, the man had yodeled for the Seven Dwarfs, had sneezed Sneezy's sneezes, had played a waterfall, a calliope, a rainstorm, an outraged bear and the chipmunks Chip and Dale and who knows what else. His Mickey matched the original so perfectly that he stayed with it until Mickey was retired 20 years ago.

(Mickey's own popularity worked against him finally. He was so revered the world over as our ambassador of silliness--as El Raton Miguel, Michel Souris, Miki Kuchi, Topolino or Musse Pigg--that he turned a bit stuffy, becoming a straight-mouse and all-round goody-goody, and it was Donald Duck, with his quacking rages and his runaway id, who got all the laffs.)

But Mickey is coming back. First, the renovated 1940 "Fantasia," with a million dollars' worth of brand new digital sound, will show him off once more as the Sorcerer's Apprentice, his greatest classical role. It was the first time his eyes had pupils, by the way. And later this year he will appear in "Mickey's Christmas Carol," with a $3-million budget and a new voice, for MacDonald retired five years ago.

"It's pretty simple, just a plain falsetto," he says. "You can't make any sustained speeches because it's all a monotone and it gets dull to listen to."

How in the world does a man get into a business like this?

"Well, I was a drummer for a band that was called in to record a cartoon in 1934. But I stayed on. Drummers have all the props, you know, the slide whistles and glockenspiels and things, and there would be three of us lined up there staring at the screen with a tableful of gadgets and headphones on our ears. I had more props than anybody."

He is a woodworker. He loves the smell of wood, has a cellarful of lathes and routers. One day at the Disney studio, where he worked for $40 a week, MacDonald was tinkering with a keg he had built and filled with dried peas. Disney happened along.

"What's that gonna be?" Disney said. He always was fascinated with sound effects.

"I think it's gonna be rain."

"I must hear that."

And he did. A week later MacDonald was called upstairs to Disney's office and given a raise to $100, "more money than I knew how to spend." It was 1935.

Once he was asked for a clarion-clear chime. He found some old brake drums, so hard they ruined all his carbon drills, tuned them to a 13-note chromatic scale to make gorgeous bell-like tones. He filled kegs with nails and other things to make several kinds of rainstorm and pounding surf. He made the shimmering music of an animated spider web from sheets of duraluminum. Another time he tuned metal disks so a character could play scales with a hacksaw. (He makes the sound: "Neeeeyowwwayowwwayowww," like a musical saw.)

For "The Fox and the Hound" he did a bear fight. This consisted of growling into either end of a kerosene lantern chimney: big end for closeups, small end for long shots.

For Evinrude, the heroic dragonfly of "The Rescuers," he rigged a six-inch spool with a rubber diaphragm and a tube through which he could blow a high-pitched mosquito whine with so much personality that Evinrude became a star.

For "The Love Bug," in a scene where a wheel comes off the title character, a Volkswagen, and races past it, only to falter, wobble and collapse, he blew up a balloon, put a BB in it and spun the thing around. It's uncanny: You can hear the wheel rushing past, slowing and finally flopping over, spent.

"The ideas? They just come. I was born to be a sound-effects man."

He has built 500 sound-effects gadgets in 48 years.

In the Disney True-Life Adventures, wild animals were filmed in sound, but often there would be a plane in the distance, or irrelevant snufflings would intrude. So MacDonald rerecorded the voices of hundreds of animals, cleaning up the soundtracks and perhaps adding just the tiniest bit of anthropomorphic appeal.

He was going to be an engineer but broke his ankle, which naturally led to his playing drums for the Dollar Steamship Lines, sailing the Pacific with a ship's orchestra. He once played tympani for Leopold Stokowski (in "Fantasia" you can see him), once played with the Firehouse Five. He and his red-haired wife, Bobbie, have been married 42 years. He says he is busier than ever since he retired. For the last six months he has been transcribing 28,000 effects into digital sound.

Now he is showing the photographer how he does a horse walking or trotting or galloping, even crossing a bridge. "A lot of guys do a three-legged horse," he says, demonstrating with the coconuts. Not him. He even alternates his hands, right-left-left-right, the way a horse trots.

The photographer asks him to pose with the lantern. He growls like a bear into it.

"You don't have to do the growl," the photographer says.

"I know. It's just a picture."

But as the photographer clicks away, Jimmy MacDonald continues to growl softly into the glass tube.