On a recent afternoon, John Schumann plugged away at his workbench in the back room of Main Drag Music, on North Fifth Street in Williamsburg, Brooklyn. Working steadily, the 42-year-old guitar pedal maker seemed oblivious to the screeches of an electric guitar and the thump-thump of a bass as customers tried out instruments on the other side of the wall in the front room of the music store.

The brim of his brown suede hat flopped up and down as he carefully placed the exposed copper end of a wire into the metal casing of a circuit board with his thumb and index finger. Such care is justified – his work ends up at the feet of bands such as Portishead and the Grammy-winning group Radiohead.

Carl Myers, who co-owns the store where Mr. Schumann manufactures and sells his popular line of guitar pedals, says that Mr. Schumann’s “major handicap is that he’s always coming up with new stuff. Most people are just rehashing old ideas,” Mr. Myers said.

Mr. Schumann isn’t like most people. Born in Reigelsville, Pa., he taught himself how to play guitar and initially made a living as a mural painter while playing in various bands (Kidsilver, Toulouse, and Poka-Poka) before his interests turned to the mechanics of music. After a few failed attempts at building a ninestring guitar, Mr. Schumann turned to electronics, teaching himself the basics by reading books on the subject and learning how to fix the 24-track at in his recording studio near Northampton, Mass., before moving to New York City in 1996 to invent and manufacture his own line of guitar pedals.

Mr. Schumann, who has been making guitar pedals for 10 years, admitted that if he had known how complicated the electronics of music were, he might have shied away from a career in the field. Yet when he was a performer, he felt that he was really “playing pedals and melodies, not guitar parts.

“The guitar was more like a control for the sound,” Mr. Schumann said.

He wanted to build pedals that would make “strange” intonations “like birds sounds and a bunch of weird stuff.” He aims to “make new sounds that don’t exist yet – variations of distortions,” which he describes as “controlled craziness.”

“I try to make something that’s really strange. I’ll look at schematic diagrams for other pedals and think, ‘How can I connect different parts to get a new result?’ Normal effects are boring. I’m just trying to make something new.”

In his dream life, Mr. Schumann would spend his days inventing pedals and sounds, while a team of technicians made them. But his world is short on magical factories and long on product demand, so he works tedious ly in the back room of Main Drag Music, attempting to fill the floods of orders that pour in each week. He’s currently 10 orders behind.

Main Drag Music carries all six Schumann pedals: the PLL (an “analog harmonizer”), Drone for PLL, Momentary Switch, the Schumann Lion, the Schumann Lion X, the Two Face Fuzz (which is only made to order) F.Loop, and the Comparator distortion pedal – all of which are compatible with guitars and basses.

Mr. Schumann’s most popular pedal, the PLL, originally brought him to Main Drag. Mr. Myers first heard about it through Mr. Schumann’s band mates and asked him to bring some in to sell on consignment. An improved version of the PLL he brought in shortly afterward sold instantly, according to Mr. Myers, “almost as quickly as John made them – as soon as they came off the assembly line.”

Word spread fast. An article about Mr. Schumann’s pedals in the trade magazine “TapeOp” resulted in orders from places as far away as Finland and people such as the members of Blue Man Group.

In 2000, acquaintances of Mr. Schumann’s, Mark Linkous and Scott Minor of Sparklehorse (an alt-rock band from Virginia), brought some pedals to England, where they were recording an album. They showed the Two Face Fuzz to Radiohead’s members. Bassist Colin Greenwood said he wished they’d had the pedal earlier, so the band could have used it on every track of the album on which they had been working. In 2002, when Main Drag moved to a larger, location, its owners invited Mr. Schumann to work on what he refers to as his “mad scientist-type” pedals on-site.

His desk and walls are cluttered with personal items – a faded “Happy Birthday John” card, a collection of abstract paintings (Mr. Schumann’s other passion), and a thank you letter from DJ BT, who used one of Mr. Schumann’s pedals on his recent dance album. Empty coffee cups sit neatly stacked next to an oscilloscope that Mr. Schumann uses to test the signals of his pedals.Thin ribbons of hot steam float from the white-hot tip of a soldering iron. In his cable knit cranberry sweater, faded black jeans, work boots, and signature brown hat, Mr. Schumann looks like a veteran musician.

A typical day might entail a few hours spent constructing the inner cores of a dozen or so pedals and soldering wires to the motherboard and dials. Alternately, Mr. Schumann might spent a morning painting the main box of the pedal black, or painstakingly peeling paint away from gold lettering on the front of each pedal with a Q-tip.

The base material for the pedal case covers comes in white (he orders the materials in bulk; parts for each pedal total on average about $100). Mr. Schumann experimented with about 50 brands of paint from Pearl Paint before finding one that would dissolve with a salve without destroying a copper sheath underneath. “I knew I could do it,” Mr. Schumann said of the precise process, “it was just a matter of finding the right paint.”

He is equally particular about making his products unique in their use. For instance, a volume of 10 on one of his pedals is closer to a 40 on average pedals. “I made them louder on purpose because I felt like pedals were never loud enough.” As a result, some people get his pedals and “have no idea what to do with them,” while “others do great things.”