When he was invited to play in Chick Corea’s Elektric Band in 1985, John Patitucci decided it was time to move from four strings to six. “Anthony Jackson inspired me,” he says. “And I felt like the new music we were playing with Chick would benefit from having a low B string. At that time, the synthesizer players were trying to take over the world, playing lower notes than the bass players, so I thought, I need that B. And also, because of my interest in becoming more flexible as an improviser, the high C string would give me some tenor saxophone range.” Patitucci went to Ken Smith’s shop in New York City, played a 6-string bass, and ordered one, which he played on three Elektric Band albums and his first two solo albums, John Patitucci and On the Corner.

Patitucci’s growing mastery of the instrument caught the ear of legendary Yamaha artist-relations man Takashi Hagiwara, who contacted Ken Dapron, a guitarist who was working as a Yamaha product manager, and told him to go see John. “I went to a show — I think it was in Irvine [California] — and went backstage,” says Dapron. “We met there for the first time, and I invited John to come to Yamaha.” Patitucci and Dapron connected immediately. “Ken is an amazing guy,” John says, “and we just hit it off.”

Dapron told Patitucci that Yamaha was developing a TRB 6-string and invited him to visit the company’s facility in Buena Park, California, to check it out. He did — and quickly decided to work with Yamaha going forward. John remembers, “What appealed to me was that I would have a lot of say in the design of the instruments, and they would work with me and make things for me.” It wasn’t long before Patitucci had an array of Yamaha basses for his touring and studio work. In my May/June 1992 Bass Player cover story about John, he told me, “All of my electrics are Yamaha TRB models; I’ve worked closely with the company on their development, and my basses are prototypes.” At the time, John had three 6-strings, including one with a whammy bar, and a 5-string with a body modified to facilitate string popping.

Those prototypes led to the first John Patitucci signature model, the TRBJP, which was introduced in 1994. While Yamaha had favored a neck-through-body design for its initial TRB 6-strings, Patitucci encouraged Dapron to use bolt-on necks for his instruments. “At one point,” John recalls, “I said, ‘What is it about the old sound that we like?’ It’s the bolt-on.” Dapron confirms that John’s input was influential in product development, and that thanks to his request, Yamaha eventually created a new bolt-on system that has been used in a number of models.

That’s just one example of the ways that Patitucci and Dapron have collaborated over the years to refine and improve Yamaha basses. Another key project was their development of a new onboard preamp. “Yamaha had come out with this digital parametric EQ,” says Dapron, “and we were in John’s studio one day for a good eight or nine hours, trying to dial it in and get the right sound.” That painstaking research led to the new 3-band preamp that was incorporated into Patitucci’s improved signature model, the TRBJP2. “That’s the preamp in my red bass, and I’ve been playing that bass for 20 years,” he says.

“Yamaha has always been very open to me making suggestions,” says Patitucci. “I’ve been frank about what I wanted and what I liked and what I didn’t like. They were very strong in their ability to implement. If I said, ‘Try this,’ all of a sudden — boom — I had two prototypes. Ken has been instrumental; he understands a lot about sound and has always been super-helpful.” Dapron says: “I’m a little older than John, and I grew up listening to a lot of the same cats that he loved. We became instant friends. It’s such a great relationship; I can’t remember a single stressful time, and we’ve been working together for more than 30 years.”

Dapron is quick to point out that he’s not a luthier and that the actual work on Patitucci’s instruments has been done by series of builders in Yamaha’s custom shop. He cites Leo Knapp and John Gaudesi for their work on the TRB signature models, and he praises Pat Campolattano for his exceptional craftsmanship on John’s latest instruments, the semi-hollow 6-strings that he has been playing for the past four years.

Patitucci says he had played different semi-hollow basses over the years and had always admired the archtop instruments favored by jazz guitarists — “So I went, Wow, maybe that’s the direction to try.” Dapron reports that they designed three versions, two using the double-cut TRB body shape and one that was a true “jazz box,” with a single-cut body. “We had never done that, and we weren’t sure how it was going to come out,” he says. “With an instrument like that, you’re always worried about feedback. We were just experimenting, and it came out great.” Patitucci describes the single-cut bass as “unbelievable,” saying it has “the biggest, fattest sound of any bass I’ve ever had.” He featured it on his stunning 2015 solo album, Brooklyn. He’s also been playing the other semi-hollow prototypes recently, saying, “I’m learning about the smaller ones, which I dig, but I’m still in love with the big one.”

Dapron says that Yamaha has no plans to market the semi-hollow basses, citing production difficulties and cost factors, but he’s confident that more low-end R&D innovations will be forthcoming from Patitucci. “John’s always exploring,” he says, “and I’ll be shocked if he doesn’t come up with more great ideas.”