Fender’s Pro Reverb—This Underdog Can Growl!
Embracing and overcoming the quirky qualities of an under-appreciated hero of tube tone.
As a guitar player, I consider guitar amps to be tools. The more varied work I do, the more tools I need. There are some amps that excel in one or two things but often disappoint outside their playing field. These amps require experience to dial in good tones and to pair with guitars and other gear.
This month’s amp is an underdog—a jack-of-all-trades but master of none. It is a tool you can bring with you to any type of practice or gig, small or large, and it will deliver. It truly lives up to its name: the Pro Reverb. So, let me explain why I love this amp … but also what annoys me about it, and what I do to get around that.
In 1963, Fender offered a single-speaker Pro amp with front-mounted controls. Various Pros with top-based controls had been in Fender’s line since 1946. In ’65, the Pro was replaced by the Pro Reverb, loaded with 6L6GC power tubes in a classic Fender push/pull class-AB configuration. The Pro had either a single 15"CTS ceramic speaker or a Jensen C15N. The Pro Reverb came as a 2x12, with either Jensen C12Ns, Oxford 12L6, or Oxford 12T6 speakers—the latter a very underestimated speaker and comparable to the more famous C12N. In 1967, a silver-panel model followed and was available through 1969. Several other speakers, including models by Utah and Rola, came throughout the ’70s. And around 1978, a 70W version of the Pro emerged, with master volume and a push/pull boost, for a roughly five-year run.
The differences between the single- and dual-speaker black-panel Pros were most importantly the speaker configuration and the addition of reverb in the vibrato channel. There were two different versions of the output transformer: the 8-ohm 125A7A and 4-ohm 125A6A. This smaller output transformer is found in several medium-sized amps, such as the Vibrolux Reverb, Bandmaster, Tremolux, and also the rare and coveted 1964 Vibroverb.
How does it sound to play through a Pro Reverb, with its combination of the classic black-panel AB763 tone stack, dual 6L6GCs, a large and bass-y 2x12 cabinet with a 5U4GB rectifier tube and a small output transformer? Beautiful, full, clean tone at lower volumes and wildly cranked tones when pushed—much more than you’d expect from such a big Fender amp. Very few amps can do both of these sonic profiles.
Please find a Pro Reverb and plug in your Telecaster for a real Keith Richards experience, with one of the best rhythm tones there is.
The large open-back cabinet means you can point the Pro in almost any direction and fill the room or stage. At home, I sometimes want the most natural break-up from the amp at lower volumes, so I simply disengage one of the speakers and insert a 12AX7 in the phase inverter slot. I think the Pro Reverb delivers the most elegant and balanced cranked tones of all black-panel amps. I also love that the amp offers a bright switch that will support pedals and guitars well.
One annoying thing about the Pro is the lack of a mid pot. Since it is that good at delivering cranked tones, I would like more mids for heavier distortion at lower volumes without having to disengage speakers or swap tubes. A mid dial would also improve EQ control, for playing clean. Without a mid knob, I often have to dial the bass knob all the way down due to the bass-y cabinet and flabby output transformer. The solution is, as always, installing a switch on the back of the amp that toggles between the stock 6.8k mid resistor and a 25k. The Pro Reverb is the amp that benefits the most from this mod, I think.
Finally, do we really need a Pro Reverb in our toolbox? The Deluxe Reverb and Vibrolux Reverb are also low/medium wattage amps. Both are lighter, more snappy, more practical at home or in the studio, and don’t carry two large 12" speakers, which are overkill for the Pro’s light output transformer. The Super Reverb also breaks up—and with more punch, bass, treble, and attack overall. It is also more touch sensitive. The clean-voiced monster Twin Reverb is 17 1/2 to 22 pounds heavier but does not require more space than the Pro Reverb.
Given all the superior amps mentioned above, the answer to my question is still “yes.” Our underdog can almost do all of what these legendary Fender amps excel at. But none of them will sound as warm as the Pro Reverb when cranked.
Please find a Pro Reverb and plug in your Telecaster for a real Keith Richards experience, with one of the best rhythm tones there is. Also, try a Les Paul or SG in the bridge pickup position and you might consider selling all your overdrive pedals. A semi-hollow ES-style guitar with P-90s in neck and the amp dialed-in clean will urge you to learn jazz! Please, don’t just take my word for it. Go experiment.
On The Late Show, Louis Cato Steps to the Front
The self-described “utility knife” played drums with John Scofield and Marcus Miller and spent time in the studio with Q-Tip before landing on Stephen Colbert’s show as a multi-instrumentalist member of the house band. Now, he’s taken over as the show’s guitar-wielding bandleader and is making his mark.
It’s a classic old-school-show-biz move: Bring out the band, introduce them one by one, and build up the song to its explosive beginning. It’s fun, dramatic, audiences love it, and that’s how every The Late Show with Stephen Colbert taping starts.
By this time, us audience members have been sitting in Manhattan’s chilly Ed Sullivan Theater for about 90 minutes. We’ve gotten our seats, had a bathroom break after getting settled, and had some fun with warm-up comic Paul Mecurio. The first musician summoned by announcer Jen Spyra is drummer Joe Saylor. Wearing his trademark cowboy hat, he jogs out, gets behind the kit, and kicks off an up-tempo second-line groove. Next comes upright bassist Endea Owens and percussionist Nêgah Santos. The band’s trumpeter, Jon Lampley, is introduced, and he’s brought along his bandmates in the Huntertones as guests, so saxophonist Dan White and trombonist Chris Ott come out as well.
Louis Cato feat. Stay Human "Look Within"
The multitalented Louis Cato leads the Stay Human band through a special rooftop performance of his song “Look Within,” from his album, Starting Now.
The audience is now on its feet, the band’s pocket is thick, and the energy is building. When bandleader Louis Cato charges onstage, he reaches his mic on the bandstand and shouts, “I feel good today!” with explosive enthusiasm and a big grin, and the band launches into Jon Batiste’s “I’m from Kenner.” Cato sings the catchy and gleeful refrain: “I feel good, I feel free, I feel fine just being me / I feel good today.” And the audience is feeling the love. Almost everyone is bouncing and clapping along.
A couple minutes in, when it seems like the song has reached its super-positive-vibe, high-energy climax, Cato shouts into his mic, “How do you feel today, Stephen?” And with that, Colbert comes running out from the middle of the set. Cato leaps from the bandstand toward the host as the crowd explodes. The two grab hold of each other and attempt to spin around, but the bandleader, holding his black-sparkle Tuttle T-style, loses his grip and goes sliding across the shiny stage. There’s a second where both are comically stunned—Kevin McCallister Home Alone-expressions on both of their faces—but Cato quickly jumps to his feet, both he and his guitar unharmed, and runs back to the bandstand, where he keeps the song moving along with his bandmates, who haven’t missed a beat.
All this excitement isn’t even for the TV audience! Colbert is coming out for the un-televised pre-show Q&A. In a few minutes, they’ll do a new taped intro that looks more like what we see every night. But they’ve gotten the crowd energized, and we need to keep it up. They need our energy to do their jobs.
The Late Show Band welcomes a lot of guests up on the bandstand. Here, Cato and Joe Walsh boogie down.
Photo by Scott Kowalchyk
As Cato sees it, that’s what his role as bandleader is all about: keeping the audience engaged and amplifying the drama and action of the show. “That translates to the energy that the viewers get at home,” he explains. “For all of us here, we’re able to feed off that energy and do the best possible show that we all can.”
Colbert agrees with that job description and adds that the bandleader himself has the same contagious effect on his players. “Louis is an extraordinarily gifted multi-instrumentalist,” he says, “whose spirit of creativity and collaboration not only elevates everything the band does musically but inspires me to be better at my job.” He adds, “I’m so happy to call him my friend.”
Beyond his infectious energy and charisma, there are a lot of ways Cato keeps the Late Show Band invigorated from night to night. For one, he keeps the music fresh by tackling a new cover song every day. That doesn’t mean running down rote note-for-note charts. Cato and the band take a reconstructionist approach that fans of his work—whether from his collaborations with artists such as the Huntertones, Scary Pockets, or Vulfpeck, or from his regular Instagram cover-song posts—will recognize.
“Louis is an extraordinarily gifted multi-instrumentalist whose spirit of creativity and collaboration not only elevates everything the band does musically but inspires me to be better at my job.”—Stephen Colbert
On this evening, the band runs through a host of multi-genre reinterpretations during the two-episode taping, including a slow-burning and soulful “Smokestack Lightning,” a New Orleans-style “Down by the Riverside,” and a fingerpicked, acoustic-led take of Joni Mitchell’s “Free Man in Paris” that gets Colbert lip syncing along off camera. On a horn-driven arrangement of Stevie Wonder’s “Love’s in Need of Love Today,” there’s a re-worked bridge that creates a generous feature spot for the guest horn players.
Every arrangement brings a new and unique perspective to a classic track, to ensure the band is “not just a wedding band doing a cover of a song on the radio.” Cato adds, “We’re arranging it and making it our own—because that’s the sonic fingerprint of our show.”
St. Vincent jams with Louis and crew.
Photo by Scott Kowalchyk
A Lifelong Path
Listening to the story of Cato’s musical life, it seems that this job—with its demand for a blend of careful strategizing and on-the-fly creative thinking, as well as effortless instrumental skills and charismatic showmanship—is what he’s been training for since the beginning.
On the morning of the taping I attended, I meet Cato in his dressing room. Painted with sky-blue walls and a cloud mural on the ceiling, it’s a comfortable place to hang. The bandleader is wearing slim-fit floral pants, a hoodie over a black T-shirt, and a long necklace. He sits across from me on his couch, next to a guitar stand that holds a few instruments—including his Tuttle, a Jesse Stern-built baritone acoustic, and his Univox LP-style—and a ’65 Deluxe Reverb reissue with a Universal Audio Dream ’65 pedal plugged into it.
“There’s not a time in my brain when I was not making music in some way or form,” Cato says. His mother, a pianist in the Church of God in Christ, bought her son a Diamond drum kit that he recalls having paper heads when he was just 2 years old, and she started teaching the toddler to accompany her. “I marvel at my mom,” he laughs. “Like, who buys their 2-year-old a drum kit?” After playing those drums every day for a year, he started accompanying her at services.
The family moved around a lot. Cato’s father was in the Air Force, and Louis was born on a base in Lisbon, Portugal, before moving to Dayton, Ohio. Not long after he started playing in church there, they moved again to Washington, D.C., and when Louis was 5 they settled in Albemarle, North Carolina. A few years later, Louis started playing guitar on a “little burgundy sunburst acoustic. Eventually, I busted a string and busted another string and just kept playing with four strings. I delved more into bass from playing bass lines on the acoustic guitar. So, for my 9th birthday, my dad bought me a 4-string bass.”
“I’d show up to Tip’s and we’d do a week of writing sessions with John Legend or have André 3000 in the studio for a couple of weeks.”
While it was strictly pragmatic reasons that initially drew him to the bass, he says his biggest inspiration was the bass player he knew best: his mother’s left hand. Her playing, rooted in the COGIC (Church of God in Christ) style, “involves heavy left-hand bass. I wasn’t as psyched to play bass in church since the way my mom plays is very defined. But eventually I kind of had to learn how she plays. It was always just her and me playing. And I had to learn to move with that and follow that. She’s a great bass player.”
Along the way, Cato picked up more instruments. By the time he headed to Berklee, he was playing drums, guitar, and bass as well as tuba, trombone, and euphonium. “I was going from being a big fish in a small pond to a small fish in a large pond of super-talented people who had heard oodles of music I had never dreamed of,” he recalls. So, he decided to focus his studies on the instrument he’d played the longest.
Louis Cato's Gear
A glimpse at Cato’s pedals and amp, which mostly live outside of the camera’s eye, behind his stage monitor.
- Univox LP-style
- Tuttle Custom Hollow T
- 1961 Gibson SG reissue
- Martin OM-28
- ’65 Fender Princeton Reverb reissue
- Boss FV-500H Volume Pedal
- Boss TU-3 Chromatic Tuner
- Dunlop Cry Baby
- 3 Leaf Audio Octabvre
- J. Rockett Archer
- Truetone Jekyll & Hyde
- Xotic RC Booster
- MXR Carbon Copy
Strings and Picks
- D’Addario EJ16 (.012-.053)
- D’Addario EXL110 (.010-.046)
- Dunlop Max Grip .88 mm
Cato completed just two semesters—fall ’03 and spring ’04—before deciding to concentrate on playing the gigs that were paying his bills. “My rationale was, much to my parents’ chagrin, here’s an opportunity where I can keep learning on the job and be working my way out of the debt I went into in this year.”
Gigging with wedding and church bands gave the multi-instrumentalist an opportunity to keep all his instrumental and vocal skills alive. “My oldest daughter was born soon after that,” he recalls, “so I felt really, really aware of how lucky I was, how lucky any of us are, to make a living and support a family as a musician.” Cato spent five years in Boston, playing various instruments in gigging bands, and he frequented local institution Wally’s Cafe Jazz Club, just two blocks down the street from Berklee, “for self-education and inspiration. When that felt like I hit a ceiling, I looked at where I could go to continue my inspiration and working on the kind of projects I wanted to be working on, and that led me here.”
By that time, Cato’s friend Meghan Stabile, had moved to New York and created the promotion and production company Revive Music, which was dedicated to the kinds of jazz and hip-hop collaborations he wanted to pursue. Cato moved to Bushwick, Brooklyn, with his band Six Figures— “There were six of us; we did not make six figures!”—and would head back to Boston each weekend for the gigs that were paying his bills. Eager to soak up the New York scene, he’d return to New York on Sunday nights and go directly to jam sessions.
All that time back and forth on the Northeast Corridor paid off. A self-described musical “utility knife,” Cato’s multi-instrumentalism, as well as his talents as a songwriter, arranger, producer, and engineer, made him a major asset as a collaborator, and the New York scene took notice. Soon, he established essential connections that would affect his career, forming “an instantaneous brotherhood that continues to this day” with producer Kamaal Fareed, aka Q-Tip. “Through that, I ended up really delving into a lot of relationships and credits.”
The two artists worked on high-level collaborations that not only bolstered Cato’s reputation but served as a major piece of his education. “I’d show up to Tip’s,” he explains, “and we’d do a week of writing sessions with John Legend or have André 3000 in the studio for a couple of weeks. Sometimes things would come from it, and sometimes nothing would come from it. But being in the creative process on that level in a trusted space was invaluable for me. I learned so much.”
Outside of Q-Tip’s studio, Cato was learning from plenty of masters, mostly from behind the kit. “It’s really special when you find yourself learning things you connect to,” he says about his work alongside artists such as bassist Marcus Miller, keyboardist George Duke, and guitarist John Scofield. “And I learned so much about myself from connecting to some of these people.”
Back in 2015, Cato received a phone call from pianist Jon Batiste. The two had never met, but Batiste rang him up about a mysterious project—a theme song for a TV show that he couldn’t disclose. “I had a wisdom tooth appointment back in Boston, and I got a random call,” Cato remembers. “I think his exact words were, ‘I’d love to have your ears on it.’ And I followed my gut, rescheduled my trip, stayed in New York an extra day with an abscessed wisdom tooth.”
The two got together to co-write and produce “Humanism,” which would become the theme song for the Stephen Colbert-hosted Late Show. Batiste played piano, Cato played the guitar, bass, and drum parts and “put on my editing hat.” They brought in Joe Saylor—who would become the show’s drummer—to play tambourine, as well as saxophonist Eddie Barbash. “After the session,” Cato remembers, “I went back, got my wisdom tooth out, and went back on the road with John Scofield.”
Three of the four go-to guitars Cato uses on The Late Show: a black Tuttle T-style, a cherry-red Gibson SG, and a Martin OM-28.
At first, Cato played the multi-instrumental role of his dreams, attempting to surround himself with every instrument he could play. “That lasted about three days before reality set in,” he laughs. “Slowly, one by one, things started disappearing—a floor tom going away here, a Pro Tools setup going offstage there. Eventually, as the band formed out, I moved around to what was needed. I was the utility guy—played a lot of kazoo, a lot of cowbell.”
While on the road drumming with Sco’, Cato got the invite from Batiste to join the show’s band, Stay Human. “It was a huge life shift for me,” Cato explains. “I was making really good money on the road with really good musicians, which was really fulfilling. And I took a chance. I loved the idea of being a part of something creatively from its inception.”
Eventually, Cato settled into a more consistent electric bass role, until Batiste brought in upright player Endea Owens, and he moved to guitar, where he’s mostly stayed. When Batiste left the show last year, Cato took over as bandleader—officially starting this season, back in September—and decided he’d lead from his role as guitarist. “Of all the places I occupied,” he says, “guitar was the easiest and most natural to me to lead the band, in the energy. From behind the drums, it’s a different thing, and we’ve done it when Joe was out. But it just was a really natural progression.”
Same Show, New Job
In just a few months, Cato’s new role as bandleader has had an impact on the show. The renamed Late Show Band’s engine seems to be burning on a new kind of fuel. And it feels as though that energy is coming directly from Cato.
When we talk, the guitarist is deeply engaged, in a kind of hyper-focused way that is not intense but more casually un-distractable. He brings that same focus to the show. While Colbert delivers monologues, Cato is zoomed in on the host, listening to every word, often riffing around on his guitar to contribute musical commentary. During interviews, he’s taking cues and following the tone of the conversation, looking for ways to adapt.
The bandleader gig requires loads of big-picture improvisation, but also lots of prep. Cato explains that each week he makes a set list, but the band will react and make changes in the moment. “My job ends up being a lot of judgement calls that affect the flow of the show,” he says. “We have a group of compositions we wrote for the show that can complement different moments. If there’s a major energy shift in an interview that takes a turn or something happens in the day, like a tragedy, we’ll call one of the songs we wrote for the show for a moment such as that. Recently, we had a guest on that started improvising a song. So, I have on our in-ear mic and call out the key and start playing, and we all jump in, and now we’re doing this instead.”
Cato poses with his black-sparkle chambered T-style, made by Tuttle. “When I’m checking off core priorities in sound,” he says, “if I’m going for rhythmic things, I go to the Tele.”
Photo by Scott Kowalchyk
Watching the Late Show Band in person, I see this play out as Treasury Secretary Janet Yellen explains the steps the U.S. can take to avoid a recession. It’s a heavy and heady conversation, and, frankly, it’s anything but fun. Cato knows he’ll need to pick the audience back up. As he watches from the bandstand, he gives tempo cues to the band, who nod along, so they can effectively shift the energy and get the audience re-focused for the next guest, actor/director Sarah Polley.
As a guitar player, Cato says he sticks to playing things that feel most natural to him so he can concentrate on his bandleading duties. He adds that he considers himself more a rhythm guitarist than a lead guitarist. (It’s worth noting that his delineation is more conceptual than musical: Cato is an inspired and dynamic melodic lead player, but his deeply rooted phrasing and feel is at the forefront of everything he plays, so the rhythm-first thing applies to it all.) “This is not a space as a guitar player where I’m jumping out of the box trying any and everything and exploring,” he explains. “You get to some of those places. But for me, it always has to start from something I can do while leading the band and reading the energy and making judgement calls.”
“We’re arranging it and making it our own—because that’s the sonic fingerprint of our show.”
That rooted, pragmatic ethos applies to the gear he chooses as well. “I never was a big gear person,” he admits. Luckily, he has Late Show Band tech and informed gearhead Matt Mead to help him keep his pedalboard well-stocked. “There’s so many things I’m learning about the job and trying to keep straight in my head that this ends up getting the short end of the stick, and it wouldn’t work if there was not a Matt Mead to make up the rest of that stick and make it sound good.”
“The show throws a lot of curveballs,” Mead points out. “He steers the boat as far as the tones he’s looking for and if there’s a particular sound he’s looking for. Sometimes, I’ll recommend stuff and say, ‘Hey I notice you’re doing this, maybe we should try this.’”
Cato’s collaboratively curated pedalboard is pretty simple at its core: It starts with a Boss FV-500H volume pedal, a Boss TU-3, a Dunlop Cry Baby, and 3 Leaf Audio Octabvre. Cato shows me how he uses the latter for more traditional, Hendrix-style playing, but he points out that the band plays a lot of montunoes, and he tends to use the octave pedal for those. For drive, he uses a J. Rockett Archer and a Truetone Jekyll & Hyde, which are followed by an Xotic RC Booster and an MXR Carbon Copy, all into a Fender ’65 Princeton Reverb reissue, and powered by a Voodoo Labs Pedal Power Plus.
In live performances outside of The Late Show, Cato uses various guitars, but says that the studio’s cold temperature doesn’t do many favors for instruments such as his Gibson Luther Dickinson ES-335 or some of his acoustics, so he’s careful when selecting which guitars come on stage at the Ed Sullivan Theater. The three guitars that most commonly appear on the show are his black Tuttle Custom Hollow T, a cherry red Gibson SG 1961 Reissue, and a Martin OM-28.
Another guitar that sometimes appears on the Late Show is his LP-style Univox, which I ask Cato about in his dressing room. “If I need to be altogether comfortable,” he explains, “I pull out the Univox, because it’s my earliest guitar. I’ve had this since high school.”
Cory Wong "Lunchtime" - The Late Show's Commercial Breakdown
When musical guests visit The Late Show, they get the full-band treatment from Cato and company. Here, Cory Wong sits in for a rhythm guitar showdown of the highest level.
Back when he first got the guitar, Cato remembers, it was in rough shape, desperately in need of wiring and pickup repairs and a new set of tuners. It stayed that way until he was in Boston. When he picked up a wedding band gig playing trombone and guitar, he was lucky enough to have a roommate who could get the Univox performance-ready by replacing the original tuners with locking units, cleaning out the electronics, and swapping the pickups for a pair of Seymour Duncans.
“I didn’t even know there was a such thing as a professional musician.”
But Cato says that even before those repairs, he’s always “loved it because it’s all I had. I remember I was playing a little Vox amp, and this guitar had a feeling out of that amp. This guitar just became home base and felt super natural to my fingers. If I need to just not be thinking at all, this is home.”
Did he ever dream he’d be on television every night, holding this Univox and chumming with a late-night host? “Never! Not once!” he says. “It was just a product of my nurture growing up in a small town. I didn’t even know there was such a thing as a professional musician.” And yet, Cato pursued music as fully and single-mindedly as he could. “I just knew that I liked it and felt connected to it.”
Getting the Most Out of a Classic Twin Reverb
A brief history of Fender’s heavyweight champ amp—plus, how to make it float like a butterfly and sting like a bee.
“If an alien came to earth and wanted to hear an American guitar sound, I’d play him my Twin with a set of Jensens.”
I found this statement many years ago and it summarizes my feelings about the Twin Reverb, the flagship of Fender amps. So, let me share my insights about the biggest brother in the Fender family and discuss speakers, tube swaps, and how to unlock its secrets. My goal is to turn you all into educated fans of this legendary amp that has somewhat lost its place in the modern world. But first, a few facts.
Fender released the Twin Reverb as we know it today in 1963 as one of the first black-panel-era amps. It was a dual-channel combo with two 12" speakers, a diode rectifier, reverb, tremolo, and four 6L6GC tubes producing 85 watts. It was targeted at professionals and was the most powerful amp Fender had ever made. During the earlier tweed era, the Twin arrived as a 2x12" combo amp—first, a low-power 25-watt version with a single power tube pair; then, after 1958, a high power-version with four 6L6GC tubes and 80 watts.
“Speakers are like ice cream—everyone has their favorite.”
The blonde Tolex Twin came in 1960 and looked more like the black-panel classic that we know today, with separate normal and vibrato channels on the faceplate. Reverb and a diode rectifier were added to the black-panel Twin Reverb, which had all the features and the biggest iron that Fender could offer at the time. It was the first and only black-panel amp with a full tone stack on both channels, with bass, mid, treble, and a bright switch allowing you to dial in everything between a Dick Dale Strat surf tone and a mellow jazz sound for, say, a big box Gibson. The silver-panel Twin Reverb went through several changes from 1972 onwards, mostly in the power circuitry. There was a 100-watt and 135-watt silver-panel version with master volume. They aren’t very popular today but will work well as a cheap practice amp if you can find one in good condition.
The cons of the Twin Reverb are weight and loudness. Depending on the speakers, a Twin weighs 73 to 88 pounds. The 13-pound JBL D120F speakers that came in the original black-panel Twins were, in my opinion, too heavy for the amp, as were the four 10" JBLs in the Super Reverb. While these speakers are highly collectible, the weight of these ceramic JBLs will eventually tear the wooden cabinet apart. So, you cannot transport these amps around for regular touring.
My favorite vintage speakers for the Twin Reverb are the lighter Jensen C12N (7 pounds) or the Fender Oxford 12T6. The Oxfords sound surprisingly tight and good, and not as mushy as the Oxfords you find in other, low-powered Fender amps. The 1965 reissue black-panel Twin Reverb’s modern Jensen C12Ks sound unforgivingly stiff to my ears. Even if they improve after years of playing, I prefer to replace them with the lighter Jensen P12Q, which has a smaller voice coil and a vintage steel basket, or Warehouse Guitar Speakers’ brighter G12C/S. The G12C/S delivers a great authentic Fender tone at a reasonable weight (10 pounds) and price. But don’t solely trust my speaker advice. Speakers are like ice cream—everyone has their favorite. With the right speakers for your ears, a reissue Twin Reverb will deliver all the goods for you.
While other Fender amps typically break up at around 4 with a Strat, the Twin Reverb stays clean up to almost 6—and those clean notes are sharp as a knife’s edge and will hold up against heavy drummers and bass players. This is exactly what the amp is made for: being played un-miked in, say, a gospel band in a 300-seat church every Sunday, or on Friday nights in a cowboy bar in Bakersfield, circa ’63. It is designed to not break up. You therefore need to have your expectations set correctly—or be adept with pedals—to really appreciate the evil Twin.
A simple trick to lower the headroom is to disengage one of the speakers and pull the two inner or outer power tubes. You will, then, essentially, have a 1x12" 40-watt amp while still benefiting from the ambience of the large speaker cabinet. Other than that, there are no mods that I recommend with this amp. The Fender Twin Reverb is made for big occasions, and once you learn how to use it correctly, you’ll enjoy a very physical tone experience together with everyone else onstage—who will have no problem hearing this amp. I promise.
Game of Tones
How to expand classic Fender amp sounds with different speaker configurations.
As you know, replacing or augmenting the speakers of your Fender amps is the easiest way to organically change your guitar tone. So, let’s discuss some alternative speaker configurations for classic Fenders. We’ll also explore some basic knowledge about resistance, current, and power distribution along the way, which will enable you to safely experiment.
If you are replacing or adding speakers, it is important to verify that all speakers are in phase and that you wire the plus and minus terminals correctly. Otherwise, the speakers will cancel each other out and the result will be a thin, weird tone without much bass or character. This rule applies to all speakers in the main amp and in extension cabinets. For all the examples in this column, I will refer to 8-ohm speakers wired in parallel, if not explicitly mentioned otherwise. I will also use both the terms “impedance” and “resistance,” which are commonly used in these conversations, even though the correct term for speaker resistance is impedance. Got that?
Now, let’s use a Deluxe Reverb as an example. The most common trick to create a bigger tone and more spread from a Deluxe is adding a second cabinet with a 12" speaker. The Deluxe has just enough power to drive them both. However, I’ve found that the Deluxe’s 22 watts is not enough for adding a 15" speaker. The bottom end gets too loose and farty. For that option—which features a full clear bottom end and opens up the array of overtones—I would typically recommend a bigger, 35- to 40-watt amp. But there is an option for adding a 15" speaker to a lower-powered Deluxe. You can replace the 6V6s with 6L6GC tubes for more power. Then, adding a 15" speaker makes sense.
“It is important to verify that all speakers are in phase and that you wire the plus and minus terminals correctly.”
Here comes a few even-more-advanced tricks with the Deluxe Reverb. The first: Replace the original 1x12" baffle with a 2x10" baffle for snappier low-end response, more sparkle, and a more scooped tone. It is very easy to cut out a solid pine board and staple grille cloth onto it. With two 10" speakers, the total speaker impedance also changes from 8 to 4 ohms, and will suit the 6L6GC tubes better, since they have a lesser output impedance than the 6V6 tubes. After that mod, if I want to play at lower volumes, I unplug one speaker and use the Deluxe Reverb as a single 1x10".
An even more creative and rarer variant is to use both 10" speakers together with a 15". In this setup, you have to wire the two 10" speakers in series and connect the 15" via the external speaker output. The amp will then see two resistance branches in parallel:
- Branch 1: the two 10" speakers = 8 ohms + 8 ohms, for 16-ohms resistance.
- Branch 2: the single 15" speaker = 8-ohms resistance.
The current always wants to follow the path of least resistance, so the second branch with the 15" speaker will get twice the amount of power and current as the first branch. And since there are two speakers in the first branch, that total branch’s power is divided equally between them. This results in a roughly 67 percent + 17 percent + 17 percent power distribution for the three speakers. This is a healthy and good-sounding balance, since a 15" speaker requires and can take a lot more power than a relatively tiny 10" speaker. Be aware that you must not use the amp in this configuration without the 15" plugged in, or you will damage the power tubes. The amp expects a 4-to-8-ohm impedance with the 6L6GC tubes. The two 10" speakers alone at 16 ohms is too far outside the safe operating range.
I will also briefly mention a change-up for the 2x10" 35-watt Vibrolux Reverb. If you want more punch and a bigger low end from this model, you can replace one of the 10" speakers with a powerful and efficient 12". I have had great fun fitting a 12" Celestion Alnico Gold on the preamp side of the amp and a lighter, neodymium Jensen Jet Series Tornado 10" on the power transformer side of the amp, where there is less physical space for a big speaker magnet. You now have three power levels: the 10" alone, the 12" alone, or both together for maximum punch. I can even add another 12" external speaker cabinet via the external speaker output for a mega spread on big stages. If I want to add a 15" extension speaker, I prefer to disengage the internal 10" and use the 12" and the external 15" together. My favorite modern 15" is the Eminence Legend 1518. It is impressively responsive. Also, it balances nicely with a classic vintage black-panel Fender tone.
I hope these ideas and tricks inspire you to experiment with speakers.
Acoustic Guitars and Fender Amps
Interested in plugging a flattop into your favorite silver- or black-panel beauty? Here’s what you need to know.
Have you ever tried to plug your acoustic guitar into a classic-style Fender amp? There are some hurdles to overcome, and this month I’ll provide some advice on how to get past them. But first, some background.
Amps made for electric guitars are carefully designed and matched to the voltages and frequency profiles of signals delivered by electromagnetic pickups. An amp sounds best when it does a good job at amplifying or filtering out certain frequencies. So many of us have stumbled upon challenges when the input signal—say from an acoustic guitar or other instrument—is way different than what the amp expects.
A guitar signal is initially created by moving the strings. The more vibrating metal mass closer to the pickup’s magnet, the more magnetic pull and more current is induced inside the coil wire in the pickups. More windings and stronger magnets induce more current, but also reduce brightness and clarity. The coil-wire thickness, wire material, and coating material and thickness also play a role in signal strength and frequency response. The signal voltage produced by a pickup is low—typically between 0.1 and 1V—and contains frequencies between 80 and 1200 Hz.
On the amp side, there are even more factors that amplify or weaken certain frequencies—so-called frequency filtering. Take a vintage Fender Deluxe Reverb. It is designed with specific tubes, resistors, and caps in the preamp stage to amplify a weak input signal and shape it through EQ, mix in some reverb, and transport the result to the power amp circuit, which does three things. First, it splits and duplicates that result into an inverted signal, then it amplifies the two signals as much as possible, and then feeds them into each side of a power transformer that alters the resulting voltage to a suitable level for a loudspeaker. That’s typically 30 to 50V. The speaker cabinet and loudspeaker itself are the final stage in delivering a filtered and amplified guitar tone.
For acoustic guitars I prefer modern American-style speakers that can handle high power and both a firm bass response and a crisp top end.
If you hook up other instruments, like an acoustic guitar or a harmonica with a microphone, and feed an electric guitar amp their signals, you will get totally different results throughout the circuit. You may not get the tone you expect, or, in the worst case, you might damage the amp. But generally, all passive sources with electromagnetic coil pickups are safe to use. This includes piezo pickups mounted to the bridge of an acoustic guitar and vocal microphones. Since they are not powered by an external source like a 9V battery, they are passive and create a weak signal.
You should be careful using electrically powered sources like an acoustic guitar with a battery-powered preamp and EQ. Also, electric pianos, synthesizers, or Bluetooth speakers with mini-jack outputs are dangerous, too, since they can easily blow the loudspeakers due to a wrong volume or EQ setting. Electric pianos can sound very good through a vintage Fender amp. I’ve seen Fender Rhodes keyboards played through Twin Reverbs, and we’ve all heard organs through Leslie/Vibratone speakers, which can be run by Fender guitar amps.
Acoustic guitars with active pickups can be difficult. With typical default amp settings for electric guitar, the tone is narrow and focused around certain mid frequencies. It lacks fullness, top-end clarity, and overall balance. So, I have some tricks you should try if you’re experimenting with this option. First, set all the EQ knobs to 10. This allows the guitar signal to travel through the preamp section with minimum change of tone. Be very careful with volume and start low—at around 1.5—and increase from there. I find big, powerful Fender amps are best for this, since they have plenty of clean headroom and wide EQ possibilities with a full set of bass, mid, treble, and bright-switch controls. And that makes them less prone to howling feedback.
A big speaker cabinet will enhance the low end, allowing the preamp and power amp to relax more without maxing out clean headroom. Remember that the power and energy lie in the bass. I suggest the silver-panel 40-watt Bandmaster Reverb and 85-watt Showman Reverb as practical amp heads for acoustic purposes. I use my Bandmaster Reverb with a 1x12 extension cabinet loaded with an Eminence Maverick. For acoustic guitars, I prefer modern American-style speakers that can handle high power and both a firm bass response and a crisp top end. Speakers are very important for your tone. The guitar’s pickups are also important, together with a correct setup, so the action permits the optimum proximity of the pickups.
Acoustic pickups don’t have to be expensive. They just need to be balanced and clear. A good guitar amp and some careful adjustments of the controls will do the rest.