Inside a plain-looking, beige two-story house in Inver Grove Heights, art is being made.

Art, with strings attached.

Welcome to Brown's Guitar Factory, a guitar repair and restoration shop where owner John Brown and his team of three luthiers build some of the most beautiful and innovative electric basses and guitars on the market.

"People say the 1950s and '60s were the golden age of guitar making," said Brown. "But we have collectors who think the finest instruments are being produced today in the small shops around the world."

His is one of the many shops that cropped up in the 1970s in response to complaints about the quality of mass-produced guitars. Boutique builders were offering what the Fenders and Gibsons could not: instruments made in limited quantities, crafted by hand instead of machine.

And although most boutique builders focus on electric guitars, Brown's is known for its bass guitar.

"[Brown] could build a bass in two weeks, but he knows it would be an inferior product and he wouldn't do it," said John Payne, lead singer and bassist for the rock band Asia featuring John Payne, who commissioned a signature bass in 2010. "He's not a fast-food luthier. He really is a master craftsman."

Built to customer specifications with a variety of tonewoods and electronics options, the basses feature Brown's patented design that raises a section of the fretboard surface to the height of the frets, allowing the instrument to keep its proper scale while providing smooth playing action.

A factory in name only, Brown's Guitar Factory is more like a workshop, spread out over three floors of a small house crowded with parts, equipment and cases holding guitars awaiting repair.

Production starts in the basement, where the bodies and necks are shaped with hand tools and hours of sanding. The finish-spraying room is a tight space tucked under the basement stairs. Repair work and tool production are done on the main floor, which also has the business office and a limited display area. To get to the second floor, where the wire coils of the magnetic pickups are hand-wound, you have to go through the bathroom to get to the stairs.

"We're pretty maxed out here," Brown said. "We'd like to grow the business, but it has to be the right kind of growth."

For Brown, 47, building and repairing guitars is in his blood. A third-generation stringed instrument sales and repair shop owner, and former performing musician, he built his first guitar in the early '80s and has been looking for ways to improve guitar designs ever since.

"I'm influenced by everything," he said. "I don't want to ignore what I hear and what I see and what we can come up with."

Guitar building has taken on a greater emphasis within the business, but Brown said that he started by repairing guitars and making tools to do that work. His shop gained a strong reputation for quality work, especially when restoring valuable vintage guitars, such as a 1952 gold-top Gibson Les Paul. It required a neck reset and the owner requested that the existing finish be preserved as much as possible.

"A refinish needs to be done right because it is a make-or-break thing," said Adam Meyer, who has worked for Brown for a dozen years. "We used to do more restorations, but we definitely build more now."

Brown and his team build five to seven guitars a year amid the confines of the small house. With prices starting at $3,500, his guitars are geared more for the serious players and professional musicians who have the time and money to get a custom-made guitar.

Soon after Payne and Brown met at a guitar show in 2009, Brown called Payne to share his idea of making a signature instrument for the bassist. The two talked weekly for the next year about every detail, including the rare Padauk wood for the body.

Payne still chuckles at the memory of Brown wearing white gloves when he presented the finished bass.

"He poured his heart and soul into this guitar," he said. "To me, this instrument is priceless and it's something I could never part with."