Our columnist is really passionate about cleaning up his tone.
Our columnist breaks down why Leo’s original designs are still the benchmark for pristine guitar sounds.
It’s time to discuss a favorite topic of mine: the Fender clean tone. I’m a big fan of pristine guitar tones, and I think it might be the reason why I got into Fender amps in the first place. So, in this column, I’ll break down and explain what creates the beautiful, crystalline tone in vintage Fender amps, and share which amps are best for capturing these huge, squeaky-clean sounds.
Among my music friends, I am known for advocating these tones. Sometimes my bandmates want more distortion and growl from my guitar, but I proudly resist and argue that the music we create profits from a clearer guitar tone. It’s not about volume and distortion; it’s about melody, rhythm, and dynamics. Personally, I find it more interesting to hear guitarists with clarity, where I can identify single notes and what they are doing. It’s much harder to play clean, and the transparency forces us guitarists to consider more carefully what we play.
Tone and music are definitely matters of personal taste. What someone finds naked and thin, others will find clear and articulate. Let me therefore explain my definition of “clean tone.” A good, clean tone means clarity and little distortion. Clarity is achieved when there is a certain balance between the frequencies. There must be enough sparkle and brightness together with a firm low end. In my definition, you can also have some distortion as long as you have enough clarity to hear single strings in a chord, which some define as a “bell-like” tone. Muddy or overwhelming mid and bass frequencies will spoil this clarity. I like punchy guitar sounds, and for that we need muscle and power from large power-amp sections and larger speaker cabinets. But again, there must be enough sparkle and treble attack to balance that big low end.
The black- and silver-panel Fender amps excel in this area. Fender designed these amps specifically to support the music style of the 1950s and ’60s: Whether it was folk, country, rock, or surf, the guitars were supposed to be bright and clean. The amps therefore had to produce a sound that was both clean and loud, often without PA systems.
There are several reasons why these Fender amps sound the way they do. Let’s dive into the most important factors. Firstly, the tone stack and EQ section play a significant role in creating a scooped tone with few mids. Most AB763 Fender amps have 250 pF, 0.1 μF, and 0.022 μF caps (treble, mid, and bass, respectively), controlled by 250k bass and treble pots and a 10k mid pot (or a fixed 6.8k resistor in amps without the mid pot). If you alter the value of the mid resistor or insert a larger coupling cap after the preamp section, you will get more, and earlier, breakup. If we look at the preamp sections of the AB763 amps, there is no tube gain stage, whose purpose is to introduce distortion. There are only the necessary tube gain stages to mix and lead the signal to the power amp section.
“Fender designed these amps specifically to support the music style of the 1950 and ’60s: The guitars were supposed to be bright and clean.”
The power amp section is equally important. The AB763-style amps have dual power tubes in a Class AB push-pull configuration which has significant clean headroom—more than single-end Class A amps. The fixed-bias design provides more headroom than cathode bias, which creates sag and less headroom. The efficient long-tail phase inverter and the negative feedback loop are also used to minimize clipping. Finally, using American-style speakers in the open-back cabinet design of the black- and silver-panel combo amps will enhance bright frequencies and tame the mids and low end. All these details point to one conclusion: Fender designed the AB763 amps to achieve the cleanest possible tone.
For me, the cleans of a Super Reverb are especially fantastic. The four, lightly driven 10″ speakers produce a scooped sound with great dynamics and touch sensitivity. The full set of EQ controls, robust power amp, and large transformers work together to give you both sparkle and a firm low end, even at high volumes. The Pro Reverb and Princeton Reverb, however, will struggle to stay clean when pushed. The relatively small-output transformers are a bottleneck in these amps, and they both lack the important mid control to tame the bass and mids. The Pro Reverb’s boomy 2x12 cabinet gives a flabby bass response, and the Princeton Reverb has a cheaper and inefficient phase inverter. This means that these amps can play clean only at lower volumes. If you read my previous articles on these amps, you will find easy instructions for how to improve the clean headroom, if that’s what you want.
If it’s natural distortion you’re after, the best black- or silver-panel Fender amp is the AB165 Bassman. But that’s a different story we’ll come back to later.
Our columnist is back to balance the force with a look at the top qualities of old-school Fullerton noise-makers.
Last year, I wrote a column listing the top 10 annoying things about vintage Fender amps. Now, I seek to rebalance the equation, and will share my list of reasons to love them.
There are countless reasons why simple, vintage Fender amps are still the tool of choice for many working musicians, both onstage and in the studio. I suppose my list is also colored by the fact that I am an electrical engineer, just as Leo Fender was. I have traded and serviced them for almost three decades. As usual, I will mostly refer to the black-panel and silver-panel era of amps from the 1960s and ’70s.
1. Circuit standardization
The amp techs among us may have noticed how similar the electrical circuits are in the various Fender models, especially the popular black-panel Deluxe, Vibrolux, Pro, Vibroverb, Super, Twin, and Showman. Many of us use the nickname “AB763” amps because they are based on the same electrical circuit design, and some are almost identical on the inside. Yes, there are some differences, but apart from the power levels and size, they follow the exact same recipe with the tube layout, preamp section with tone stack, the long-tail phase inverter, the class-AB push-pull power tube design, fixed bias, negative feedback loop, and so on.
So, the tonal differences between the black- and silver-panel-era amps are explained by cabinet size, speaker configurations, speaker type, and power levels. Once you learn how to work on one model, you can work on them all.
2. Circuit simplicity
The first time I opened a Fender amp and inspected its innards was in 1998 when I got my first vintage one, a 1965 pre-CBS Super Reverb. I was surprised by how simple and organized the circuit was. The few components were laid out in patterns and functional sections, and the wires were cut in perfect lengths and bent nicely, tying everything together in a way that was easy to understand when I followed the circuit layout diagram. Simplicity means fewer things that can go wrong. These qualities also make maintenance easier for amateurs and enthusiasts.
3. Low-cost physical construction
Back in the day, Fender was concerned about cost and weight, and as a result, there was no high-end selection of materials or advanced mechanical features. If you need to repair or rebuild something, you don’t have to rebuild with absolute vintage correctness to obtain the original Fender tone. If, for example, an MDF baffle board is damaged, which tends to happen to amps with multiple heavy speakers, I always use thicker pine plywood when cutting out a new board. The tone remains pretty much the same, while robustness is drastically improved. This also goes for cabinet pieces, back plates, screws, and nuts. Do what Fender did, and use what you have available.
4. Tube mods
As a player, I like simple tube-swap mods, and as an engineer, I am impressed at how vintage Fender amps handle different tubes, or even allow you to pull some tubes out. Did you know that you can remove V2, V3, V4, and V5 in an AB763 amp, and the normal channel will still work?
My favorite tube swaps are a 12AX7 in the phase-inverter position for less headroom; a 12AU7 as a reverb driver for better reverb control; 6L6s in place of 6V6s in the Deluxe Reverb for cleaner headroom; and a single 6L6 in the Princeton Reverb for less headroom. There are plenty other tube swaps that you can learn about on my website, fenderguru.com, or in previous articles here at Premier Guitar. You risk malfunction and burned tubes and components if you insert the wrong tubes, so be careful and trust only valid sources.
5. The big lineup
In my list of problems with Fender amps, I pointed out a few amps that I would have recommended that Leo Fender cut out to reduce production complexity and cut costs. However, I do dig the big lineup of different amp models, from small practice amps to huge stage amps. You can pick the exact tool according to your taste and needs, and as mentioned earlier, all of them share the characteristic Fender clean tone—it’s just that some are much louder than others.
6. The clean tone
For me, the clean tone of an amp is everything. This is my number-one reason why I love the old-school Fender amps. They were designed as clean, natural tone platforms, for the simple purpose of amplifying the sound of your guitar, bass, or keyboard.
But a proper analysis of Fender’s clean tone requires a column of its own, so stay tuned for the next Silver and Black!
Which Fender amp would pair with this breezy ’65 Gibson ES-125CD?
With a few simple tweaks, you can get any classic Fender amp to cooperate with whatever guitar you like.
I find endless fascination in experimenting with different combinations of guitars and amps. Many of you may also have made surprising discoveries with certain amps and guitars as “killer” combinations. In this column, we’ll delve into the reasons behind these magical pairings, and discuss how you can modify your amp to achieve the elusive tone that lingers in your mind day and night. While having a variety of amps at your disposal is one solution, it’s undeniably an expensive and impractical one. Fortunately, knowledge is a more accessible asset. In my previous column, I explored speaker cabinets that can expand the versatility of your amp. I recommend giving it a read, as it closely ties into this topic.
Let’s begin with the Les Paul. Its mahogany body and neck contribute to a warm tone with exceptional sustain and attack, attributes further enhanced by the fixed bridge and solidbody construction. While most people associate the Les Paul with Marshall amps for classic rock tones, I find its clean tone more intriguing and often overlooked. Recently, I have discovered several live performances by American blues guitarist Mike Welch on YouTube, showcasing a fantastic Les Paul tone: bright and clean, with crucial attack that heightens dynamics and “fingerspitzengefühl”—in short, intuition and sensitivity.
Here’s my approach to achieving a fabulous clean Les Paul tone with classic Fender amps. I’ve found that amps with all EQ controls (bass, mids, treble, and a bright switch) work best for me. This allows me to rein in the bass and add top-end sparkle. For amps lacking a mid control, such as the Princeton, Deluxe, and Pro, I recommend installing a 25k mid pot in the amp’s ground-lift spot. This modification widens the tonal range from extremely icy and scooped to full British warmth. The Les Paul’s humbuckers, with their significant bass and mids, pair well with larger Fender amps that offer clean headroom and a firm low end. Personally, a Twin Reverb or Super Reverb loaded with firm, American-style speakers is my preferred mate for a Les Paul, providing enough attack to prevent muddiness in the tone.
“Hollowbodies pose a challenge, as they can generate unpleasant, squealing feedback when too close to a loud and bass-y amp.”
Now, let’s shift our focus to Gibson’s semi-hollow and hollowbody ES guitars. These guitars exhibit a bit less attack and a more vibrant, acoustic flavor. The semi-hollow ES-335 pairs well with most Fender amps, given there’s enough clarity. However, hollowbodies pose a challenge, as they can generate unpleasant, squealing feedback when too close to a loud and bass-y amp. To counter this, I prefer smaller amps for smaller venues, such as the vibrato channel of the Deluxe Reverb, thanks to its bright cap. The Princeton Reverb and the Deluxe’s left, normal channel lack the sparkle and clarity I prefer with the airy Gibson ES guitars. Since I installed a 100 pF bright cap in my 1966 Princeton Reverb, it has proven to be a perfect match. But newer, brighter speakers can compensate for the missing bright cap, too.
If you predominantly use humbucker guitars with older Fender amps, consider swapping to a low-gain preamp tube to expand the amp’s volume control range. The 5751 tube, with a gain factor of 70–80, makes it easier to dial in a sweet spot, providing more usable span on the volume control than the original 12AX7, with its gain factor of 100. Using the amp’s second, low-impedance input can also lower volume and gain, but keep in mind that you’ll lose a bit of treble in the process. Therefore, reducing the preamp tube gain is a better option.
In the single-coil league, the strategies for achieving a desired tone are almost the opposite of the humbucker league. Here, the focus is on taming brightness and generating enough warmth, especially with Stratocasters that have bright and low-output pickups. Thicker strings and increased pickup height contribute to warmth, but pushing the amp hard enough is equally crucial. This causes it to break up in both the power amp and preamp sections, creating rich harmonics in the upper mid and treble frequencies. These harmonics balance and smooth out the guitar’s scooped tone. With larger Fender amps, I may want to reduce clean headroom by disengaging speakers to increase speaker impedance, or by swapping to less efficient speakers. An easy tube mod involves replacing the 12AT7 phase inverter tube with a 12AX7 to decrease clean headroom in the power amp section. You can find details on these well-known mods in my past columns.
Hopefully, these examples can inspire you to discover golden tones with the amps and guitars you already have.