Funky Kingston: John Tu lets his hair down in tech firm's band.

Tucked back in a storeroom at Kingston Technology Co.'s Fountain Valley headquarters, John Tu is concentration personified.

With people bustling around him, Tu's collar is unbuttoned and his glasses are off. The company president is ready to get to work. But tonight's business isn't about Kingston's volatile world of computer memory products. It's about Aretha Franklin's "Freeway of Love" and "Think."

Welcome to Tuesday nights at Kingston--the sacrosanct practice night for Tu's band, JT and California Dreamin'. The band, an ensemble of horns, strings and pop music staples, practices in this storeroom, with industrial styrofoam tacked to the walls, absorbing the sound.

Tu, Kingston's co-founder, readily admits he's an amateur playing with pros.

That includes conductor LeRoy Ball, who arranges the band's music and keeps the group on tempo for performances. He's worked with famed composer and producer Quincy Jones.

"All these people have good backgrounds," Ball said.

Most of them, anyway. Scarcely four bars into Aretha Franklin's "Think," Tu loses the beat.

It's not unusual for local executives to trade suits and ties for surfboards, skydives and even guitars. But this isn't your garden-variety garage band. There are 20 members, ranging from bongo players to the backup singers.

And JT and California Dreamin' isn't trying to land a lucrative recording contract. It already has money, courtesy of Tu, who lives in Palos Verdes and is one of L.A.'s wealthiest executives with an estimated worth of $500 million.

A Chinese immigrant who fell in love with Elvis Presley as a teen, Tu takes it seriously.

"Let's say we do Chuck Berry's 'Johnny B. Goode.' No matter how good we do, at the end of the day it's still Chuck Berry's 'Johnny B. Goode,'" he said. "We need to be more than a band. We need to be entertainment. The way to do that is to add things in between the songs that are entertaining. I'm not sure quite what that is, but we're working on it."

The idea for a band started seven years ago, when Tu's wife bought him a drum set. Tu had grown up listening to rock and playing music with his friends in Taiwan.

Tu tapped some of his childhood friends to play in his band, including David Liu, who now works in senior management at Kingston. After a year or so practicing, Tu says he grew weary of how mediocre the band sounded and set out to improve it.

"We were wondering how we would sound if we had people who were professionals to play with," Tu said. "I thought that anyone we asked would look down on us and say, 'You guys are horrible!'"

It wasn't until Tu saw a band arranged by Ball at a friend's party that he found one he really liked. Ball and his brother Larry, who's played saxophone with Smokey Robinson, joined in. Then came more horns. Then a second percussionist, some background singers and dancers. Pretty soon, Tuesday nights became an event.

So how does Tu keep wanderlust musicians from leaving his band?

"He treats me well," Larry Ball said.