Note the two trimmer screwdriver slots, surrounded by blue, in the middle of this phase shifter.
Potentiometers are used for most of the controls on pedals and a lot of other electronic equipment as well. A potentiometer (also known as a pot) is defined as a 3-terminal variable resistor in which the resistance is manually varied to control the flow of electrical current. A potentiometer acts as an adjustable voltage divider. Any control on a guitar pedal that has a knob will typically be controlling a potentiometer, or sometimes a rotary switch.
There is a type of potentiometer called a trimmer (also known as a trimpot) that lives inside of some stompboxes. It typically doesn’t have a shaft that sticks up like a regular potentiometer. Trimmers usually have a slot on top for making adjustments with a small screwdriver. They are meant to be set correctly when installed in a device, and mostly never seen or adjusted by the device’s user. Trimmers can be variable resistors, variable capacitors, or trimmable inductors, and they can perform many different types of functions within a circuit.
“I know what an epiphany it can be to unlock that little extra bit of magic out of an already beloved pedal.”
I get a fair amount of questions about trimmers—often: “Is it okay to mess with that?” There are many pedals on the market that have internal trimmers that can be adjusted by users, to tweak to personal taste. It is handy to be able to dial a sound in all the way, almost like fine-tuners on a guitar. Typical user-tweakable micro controls are for modulation speed and/or width, gain, and sensitivity.
Conversely, there are trimmers built into circuits that I would not consider easily user-adjustable. These include things like bias for time-based effects and setting proper voltages so circuits can function as they should. I’ve repaired quite a few analog delays and flangers, for example, that were perfectly functional! The bias had simply drifted out of its sweet spot. Perhaps the user had gotten too curious and decided to tweak those irresistible little trimmers? Or, more often than not, the trimmers had simply drifted a bit away from their set positions over many years of use, not to mention jostling from being transported to and from gigs. A qualified pedal tech has the right meters and test equipment to get those effects dialed right back in. However, bias can be a nightmare to get back to where it needs to be without some expertise. I understand why these folks thought their pedals were broken. A modulation effect that isn’t properly biased can sound absolutely horrible!
Internal timmers, aka trim pots, come in a variety of shapes and sizes. Look for the slots.
It’s only natural to be curious about the guts inside pedals. Trimmers can add so much extra versatility to a device. If you’re ever unsure which ones are okay to tweak, a good rule of thumb is to ask the builder or the company that makes a particular unit which of its trimmers are okay to fiddle with before you twiddle. In some cases, your warranty could be voided if you do adjustments, so it’s always a good idea to check first.
I know from my own playing what an epiphany it can be to unlock that little extra bit of magic from an already beloved pedal, and I enjoy sharing any knowledge that can help guitarists get the sounds that are most pleasing out of their effects. Perhaps that pedal you planned to trade could be transformed into something you really love with a little twist of a trimmer.
A Deeper Dive
I mentioned resistors several times in this column. A resistor is a passive, 2-terminal electrical component that controls electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.
- Does your favorite stomp have an adjustable trimmer? You can find a list of popular guitar pedals that have adjustable trimmers here.
- To read more about voltage dividers, and how a potentiometer works, check this article out.
- And here’s some great information about trimmers, for further exploration.
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A rig meant to inspire! That’s Jerry Garcia with his Doug Irwin-built Tiger guitar, in front of his Twin Reverb + McIntosh + JBL amp rig.
“I met Jerry Garcia once, in 1992, at the bar at the Ritz Carlton in New York,” Dark Star Orchestra guitarist Jeff Mattson tells me over the phone. Nearly sixty-seven years old, Mattson is one of the longest-running members of the Grateful Dead tribute band scene, which encompasses hundreds of groups worldwide. The guitarist is old enough to have lived through most of the arc ofthe actual Grateful Dead’s career. As a young teen, he first absorbed their music by borrowing their seminal records, American Beauty and Workingman’s Dead, brand new then, from his local library to spin on his turntable. Around that same moment, he started studying jazz guitar. Between 1973 and 1995, Mattson saw the Dead play live hundreds of times, formed the landmark jam bandZen Tricksters, and later stepped into theJerry Garcia lead guitarist role with the Dark Star Orchestra (DSO), one of the leading Dead tribute acts.
“At the bar, I didn’t even tellGarcia I was a guitar player,” Mattson explains. “I had just heard him play the new song ‘Days Between’ and I told him how excited I was by it, and he told me he was excited too. It wasn’t that long of a conversation, but I got to shake his hand and tell him how much his music meant to me. It’s a very sweet memory.”
The Grateful Dead’s final studio album was 1989’sBuilt to Last, and that title was prophetic. From 1965 to 1995, the band combined psychedelic rock with folk, blues, country, jazz, and even touches of prog rock and funk, placing a premium on improvisation and pushing into their own unique musical spaces. Along the way, they earned a reputation that placed them among the greatest American bands in rock ’n’ roll history—to many, the ultimate. Although no one member was more important than another, the heart and soul of the ensemble was Garcia. After his death in 1995, the surviving members retired the name the Grateful Dead.
“I think Jerry Garcia was the most creative guitarist of the 20th century because he had the widest ears and the sharpest instincts,” opines historian, author, and official Grateful Dead biographer Dennis McNally, over the phone. “What we see after his death are the Deadheads coming to terms with his passing but indicating that it’s the music that was most important to them. And who plays the music now becomes simply a matter of taste.”
Dark Star Orchestra guitarist Jeff Mattson, seen here with Garcia’s Alligator Stratocaster (yes, the real one).
Photo by Susana Millman
This year marks 30 years since Garcia’s passing and 60 years since the band formed in the San Francisco Bay Area. Today, the guitarist’s musical vocabulary and unique, personal tone manifests in new generations of players. Perhaps the most visible of these musicians is John Mayer, anointed as Garcia’s “replacement” in Dead and Co. But dozens of others, like Mattson, Tom Hamilton Jr., and a young new artist named Bella Rayne, strive to keep the Dead alive.
The first few Grateful Dead tribute bands began emerging in local dive bars by the late ’70s. More than mere cover bands, these groups devoted themselves entirely to playing the Dead. A few of these early groups eventually toured the country, playing in college towns, ski resorts, and small theatres across the United States. Mattson started one on Long Island, New York. He tells me, “The first band I was in that played exclusively Grateful Dead was Wild Oats. It was 1977, and we played local bars. Then, in 1979, I joined a band called the Volunteers. We also played almost exclusively the Grateful Dead, and that was a much more professional outfit—we had a good PA and lights and a truck, the whole nine yards.” The Volunteers eventually morphed into the Zen Tricksters.
Garcia’s death turbocharged the Dead tribute band landscape. Fanbases grew, and some bands reached the point where big-time agents booked them into blue-chip venues like Red Rocks and the Beacon Theatre. Summer festivals devoted to these bands evolved.
“The first band I was in that played exclusively Grateful Dead was Wild Oats. It was 1977, and we played local bars.” —Jeff Mattson
Dark Star Orchestra launched in 1997, and they do something particular, taking an individual show from somewhere out of Grateful Dead history and recreating that evening’s setlist. It’s musically and sonically challenging. They try to use era-specific gear, so on any given night, they may be playing through recreations of the Grateful Dead’s backline from 1971 or 1981, for example. It all depends on the show they choose to present. Mattson joined DSO as its lead guitar player in 2009.
Something else significant happened after Jerry died: The remaining living members of the Grateful Dead and other musicians from Garcia’s inner circle embraced the tribute scene, inviting musicians steeped in their music to step up and sit in with them. For Mattson, it’s meant playing over the years with all the core members of the band, Phil Lesh, Bob Weir, Bill Kreutzmann, and Mickey Hart, plus former members Donna Jean Godchaux, who sang in the band from 1971 to 1979, and Tom Constanten, who played keyboards with the Dead from 1968 to 1970.
Tom Hamilton’s Lotto custom built had a Doug Irwin-inspired upper horn.
In the newest post-Garcia tribute bands, many guitar players aren’t old enough to have seen Garcia perform live—or if they did, it was towards the end of his life and career. One of those guys sitting today at the top of the Garcia pyramid, along with Mattson, is Tom Hamilton Jr. Growing up in a musical family in Philadelphia, Hamilton saw Garcia play live only three times. Early on, he was influenced by Stevie Ray Vaughan, but Hamilton’s older brother, who was also a guitar player, loved the Dead and Garcia. “My brother wanted to play like Jerry,” he recalls, “so he roped me in because he needed me to play ‘Bob Weir’ and be his rhythm guitar sidekick.” Eventually, Hamilton leaned more into the Jerry role himself. “Then I spent my entire twenties trying to develop my own voice as a songwriter and as a guitar player. And I did,” Hamilton says. “And during that time, I met Joe Russo. He was not so much into the Dead then, but he knew I was.”
A drummer from Brooklyn, by about 2006, Russo found himself collaborating on projects with members of Phish and Ween. That put him on the radar of Lesh and Weir, who invited Russo to be a part of their post-Dead project Furthur in 2009. (And on guitar, they chose DSO founding member John Kadlecik, opening that role up for Mattson.)
“When Joe played in Furthur, he got under the hood of the Grateful Dead’s music and started to understand how special it was,” Hamilton points out. “After Furthur wound down, we decided to form JRAD. We weren’t trying to do something academic, not some note-for-note recreation. We were coming at it through the pure joy of the songs, and the fact that the five of us in JRAD were improvisers ourselves.”
“We were coming at it through the pure joy of the songs, and the fact that the five of us in JRAD were improvisers ourselves.” —Tom Hamilton Jr.
Today, Joe Russo’s Almost Dead (JRAD) is considered to be one of the premier Grateful Dead tribute bands. They formed in 2013, with Hamilton and Scott Metzger as the band’s guitar frontline, with Hamilton handling Garcia’s vocal roles. Eventually, Hamilton, too, found himself jamming onstage with the ever-evolving Phil Lesh and Friends. That, of course, further enmeshed him in the scene, and in 2015, he started a band with Dead drummer Bill Kreutzmann calledBilly and the Kids.
Now, there’s a new kid on the block, literally. Bella Rayne recently turned 18 and grew up in Mendocino, California. Her parents were into the Dead, but even they were too young to have really followed the original band around the country. At her age, they were big into Phish. By the pandemic, Bella started embracing the guitar out of boredom, woodshedding while social distancing in quarantine. She explains, “Like any other teen, I was bored out of my mind looking for anything to do.” Rummaging through her garage, she came across her mom’s old Strat. “At the time, I was really into ’90s Seattle grunge. I put new strings on the Strat, and then I tried to teach myself Pearl Jam songs, and I learned how to play them by watching YouTube videos. Then, I started posting videos of my journey online as I became more serious about it. I hit a point where I knew it would be my thing. The next thing I knew, one of the Bay Area Dead bands [China Dolls] reached out to me and asked me to sit in. I thought, ‘no way.’“My parents are huge Deadheads,” she continues. “That’s theirthing. I grew up with the Dead being pushed on me my whole life. But I ended up going, and it’s just been this awesome spiral ever since.” Bella calls her current Dead-related project Bella Rayne and Friends, and she, too, has been recognized not only by the new generation of Garcia players in the Dead tribute bands, but also by Melvin Seals, the Hammond organist who played for years in theJerry Garcia Band. “I was hired to just sit-in for a couple of numbers withMelvin and his JGB band,” she recalls, “and we were having so much fun he said to me, ‘Why don’t you just sit in for the whole second set.’ It was an amazing night.”
Bella Rayne with her Alligator-inspired Strat, with a JGB Cats Under the Starssticker on the body.
Photo by Sean Reiter
Jerry Garcia played many different guitars. But for those guitarists wanting to emulate Garcia’s tone, the focus is on four instruments in particular. One is a1955 Fender Stratocaster known as “Alligator,” which Garcia had heavily modified and began playing in 1971. The other three guitars were hand built in Northern California by luthier Doug Irwin: Wolf, Tiger, and Rosebud. Garcia introduced them in 1973, 1979, and 1989, respectively. Sometimes, in a jam-band version of being knighted by the Excalibur sword, a chosen member of this next generation of Dead players is handed one of Garcia’s personal guitars to play onstage for a few songs or even an entire set.
Although they started their journeys at different times and in separate ways, Mattson, Hamilton, and Rayne all have “knighthood” in common. Rayne remembers, “In March of 2024, I was sitting in one night with anall-girl Dead tribute band called the China Dolls, and no one had told me that Jerry’s actual 1955 Strat, Alligator, was there that evening. My friend [roots musician] Alex Jordan handed me the guitar unannounced. It’s something I’ll never forget.”What’s it like to strap on one of Jerry Garcia’s iconic instruments? Tom Hamilton recalls, “It wasRed Rocks in 2017, and I played with Bob Weir, Melvin Seals, and JGB at a tribute show for Jerry’s 75th birthday. I got to play both Wolf and Tiger that night. I was in my head with it for about one song, but then you sort of have a job to do. But I do recall that we were playing the song ‘Deal.’ I have a [DigiTech] Whammy pedal that has a two-octave pitch raise on it, real high gain that gives me a lot of sustain, and it’s a trick I use that really peaks a jam. That night, while I am doing it, I had the thought of, ‘Wow, I can’t believe I am doing this trick of mine on Garcia’s guitar.’ Jerry would have thought what I was doing was the greatest thing in the world or the absolute worst, but either way, I’m cool with it!”
“I was sitting in one night with an all-girl Dead tribute band called the China Dolls, and no one had told me that Jerry’s actual 1955 Strat, Alligator, was there that evening. My friend [roots musician] Alex Jordan handed me the guitar unannounced. It’s something I’ll never forget.” —Bella Rayne
Jeff Mattson has played Alligator, Wolf, Garcia’s Travis Bean 500, and his Martin D-28. He sums it up this way: “I used to have posters up in my childhood bedroom of Garcia playing his Alligator guitar. I would stare at those images all the time. And sowhen I got a chance to play it and plug it in, suddenly there were those distinctive tones. Those guitars of his all have a certain mojo. It’s so great to play those guitars that you have to stop in the moment and remind yourself to take a mental picture, so it doesn’t just fly by. It’s just a tremendous pleasure and an honor. I never imagined I would get to play four of Jerry Garcia’s guitars.”
With young people like Bella Rayne dedicating herself at the tender age of 18 to keeping the Dead’s music going, it feels like what the band called their “long strange trip” will keep rolling down the tracks and far over the horizon. “People will be listening to the Grateful Dead in one hundred years the same way they will be listening to John Coltrane, too,” predicts McNally. “Improvisational music is like jumping off a cliff. Sometimes you fly, and sometimes you land on the rocks. When you take that risk, there’s an opportunity for magic to happen. And that will always appeal to a certain segment of people who don’t want predictability in the music they listen to. The Grateful Dead is for people who want complete craziness in their music—sometimes leading to disaster and oftentimes leading to something wonderful. It’s music for people who want to be surprised.”
“Earthwood Bell Bronze strings are a giant leap forward in tone, playability, and durability. They’re great in any musical setting but really shine when played solo. There’s an orchestral quality to them.” -John Mayer
Product Features:
- Developed in collaboration with John Mayer
- Big, bold sound
- Inspired by alloys used for bells and cymbals
- Increased resonance with improved projection and sustain
- Patent-pending alloy unique to Ernie Ball stringsHow is Bell Bronze different?
- Richer and fuller sound than 80/20 and Phosphor Bronze without sounding dark
- Similar top end to 80/20 Bronze with richer low end than Phosphor Bronze
We caught up with guitarists Carlos O’Connell and Conor Curley from red-hot Dublin indie rock outfit Fontaines D.C. for a Rig Rundown in 2023, but we felt bad missing bassist Conor “Deego” Deegan III, so we’ve been waiting for the lads to make their way back.
This time, riding the success of their fourth LP, 2024’s Romance, we caught up with all three of them at Nashville’s Marathon Music Works ahead of their April 30 gig to see what they brought across the pond.
Brought to you by D’Addario
All’s Fairlane
Curley’s go-to is this Fairlane Zephyr, loaded with Monty’s P-90s and a Mastery bridge. It mostly stays in standard tuning and, like his other axes, has Ernie Ball Burly Slinky strings.
Blue Boy
Fender sent Curley this Jazzmaster a couple of years ago, and since then, he’s turned to it for heavier, more driven sounds. It’s tuned to E flat, but Curley also tunes it to a unique shoegaze-y tuning for their tune “Sundowner.”
You can also catch Curley playing a Fender Johnny Marr Jaguar.
Twin Win
Fender Twin Reverbs are where Conor Curley feels most comfortable, so they’re his go-to backline. The amps are EQ’d fairly flat to operate as pedal platforms.
Conor Curley’s Pedalboard
Curley’s pedalboard for this tour includes a TC Electronic PolyTune3 Noir, Strymon Timeline, Boss RV-6, Boss PN-2, Boss BF-3, Keeley Loomer, Death by Audio Echo Dream, Fairfield Circuitry Hors d'Ouevre?, Strymon Sunset, Strymon Deco, DigiTech Hardwire RV-7, Electro-Harmonix Nano POG, and Lehle Little Dual.
Fake Out
Connor Deegan didn’t own a bass when Fontaines D.C. began, and his first purchase was the black Fender Jazz bass (right)—or so he thought. He later discovered it was a total knock-off, with a China-made body, Mexico-made neck, and a serial number that belongs to a Jaguar. But he fell in love with it, and its sound—nasal on the high strings, with cheap high-output pickups—is all over the band’s first record, Dogrel. Deego plays with orange Dunlop .60 mm picks, and uses Rotosound Swing Bass 66 strings.
Deegan picked up the Squier Bass VI (left) for its “surfy vibes,” and upgraded the pickups and bridge.
Also in his arsenal is this 1972 Fender P-bass (middle). (He’s a bit nervous to check the serial number.)
V-4 You Go
Deego plays through an Ampeg V-4B head into a Fender 6x10 cabinet.
Conor Deegan’s Pedalboard
Deegan’s board includes a Boss TU-3, Electro-Harmonix Hum Debugger, Boss TR-2, modded Ibanez Analog Delay, Death by Audio Reverberation Machine, Boss CE-2w, Tech 21 SansAmp Bass Driver DI, Darkglass Electronics Alpha Omega Ultra, and Dunlop Volume (X) Mini pedal. A GigRig QuarterMaster helps him switch sounds.
Mustang Muscle
Carlos O’Connell favors this 1964 Fender Mustang, which has been upgraded with a Seymour Duncan Hot Rails pickup since Romance. It’s set up so that the single-coil pickup is always on, and he’ll add in the Hot Rails signal for particular moments.
Ghost of Gallagher
Mustang MuscleAfter getting to play a number of Rory Gallagher’s guitars thanks to a private invitation from the guitarist’s estate, O’Connell picked up this Fender Custom Shop Rory Gallagher Signature Stratocaster. The jangly, direct tone of this one is all over tunes like “Boys in the Better Land.”
More Fender Friends
O’Connell runs his guitars, including a vintage Martin acoustic which he picked up in Nashville, through a Fender Twin Reverb and Deluxe Reverb.
Carlos O’Connell’s Pedalboard
The gem of O’Connell’s board is this Soundgas 636p, an imitation of the infamous Grampian 636 mic preamp’s breakup. Alongside it are a TC Electronic PolyTune, Ceriatone Centura, Strymon Volante, Eventide H9, Orchid Electronics Audio 1:1 Isolator, Vein-Tap Murder One, MXR Micro Amp, Moog MF Flange, MXR Smart Gate, and Freqscene Koldwave Analog Chorus. A Radial BigShot ABY navigates between the Twin and Deluxe Reverb.
