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.
Need more headroom or gain? Spin the bottles.
[Originally published: 9/2/2019]
You might guess from the title of this column that I love Fender amps. And you’d be right. From a musical and engineering perspective, I think vintage Fender blackface amps are the best ever made. With bright, American-style speakers, they deliver pure and natural tone. Their channels, with volume and EQ, are intuitive for any guitar, bass, or keyboard player. It’s impossible to not find a decent tone in less than 10 seconds. From a technical perspective, their handmade tube-based circuits are simple, and they were built with high-quality components. And today, there are easily available parts and schematics, and an abundance of other online technical information, which makes it possible for many techs and players—including you—to service these amps.
Classic Fender blackface amps have been an inspiration for an entire industry. They’ve appeared on countless stages and an incredible amount of great albums by legendary performers. Why? Mostly tone and clean headroom. So, for this debut column, let’s discuss what we can do to make those two factors work best for you via tubes.
Reverb and tremolo were the main functional innovations in Fender’s blackface line. The king of blackface amps, the Twin Reverb, produced 85 watts from four 6L6 tubes and had enormous power and output transformers, a non-sagging diode rectifier, and two powerful 12" speakers. The 4x10 dual-6L6 40-watt Super Reverb has half that power, a softer tube rectifier, and smaller transformers. Still, the massive array of four 10" speakers is screamingly loud and sometimes difficult to handle for its weight (65 pounds), size, and volume. A 4x10 is more directional and scooped in the low mids than a 2x12. So a guitar plugged into a Super Reverb can end up competing with the bass. Experience is required to tame these amps. Once you know how to handle them, you will be rewarded with an overwhelming and physical sonic experience.
In the blackface world, the 1x12, double-6V6 22-watt Deluxe Reverb’s advantage is that it’s small and light, at 42 pounds. It breaks up earlier than its bigger relatives due to the less powerful 6V6s, small transformers, and a small speaker cabinet. Additionally, the original Oxford 12K6-5 speaker farts out early and is very weak, although it also delivers a true signature vintage Fender sound. And who doesn’t want their amp to break up easily these days? I have kept the Oxfords in my Deluxe amps. Before the internet, few people knew they could replace the 6V6s with 6L6s and replace the Oxford to double the Deluxe’s volume.
The V6 12AT7 phase inverter tube can be replaced with a 12AX7 to reduce headroom in large 6L6 amps.
Via my website, fenderguru.com, I often get questions about how to achieve different tones in blackface amps run at lower volumes. The answer often lies in the tubes. So let me share some simple tube tricks that will help you develop an understanding of how tubes function—and how they can be used to affect changes—in the typical two-channel AB763 circuit in the Twin, Super Reverb, Vibroverb, Pro, Vibrolux, and Deluxe amps of the original blackface era.
The tubes in these circuits are typically identified as V1 through V10, looking at the back of the amp from right to left. Here are some tricks:
- The V1 12AX7 tube in an amp’s normal channel can be removed for more preamp gain and reduced headroom in the vibrato channel. It can also be replaced by weaker tubes, like 12AY7s or 5751s, for less volume/gain. I always pull out this V1 since I use the vibrato channel and want solid preamp gain, which the single V2 delivers.
- The V3 12AT7 reverb driver for the vibrato channel can be replaced with a 12AU7 for less reverb and improved reverb knob control.
- If you’re only using the normal channel, think about removing the V2 through V5 tubes for the vibrato channel. That will give you more gain and headroom in the normal channel. (FYI, the 12AX7 in the V5 position is the tremolo tube.)
- The V6 12AT7 phase inverter tube can be replaced with a 12AX7 to reduce headroom in large 6L6 amps.
- Several alternatives to 6L6 power tubes exist. I mostly use 6L6GCs. In a Twin Reverb, you can pull either the V7 and V10 or V8 and V9 tubes for half power and earlier breakup. Ideally, but not totally necessary, you should disengage one speaker to match the impedance change.
- In a blackface Deluxe, the GZ34 in the V9 slot is the rectifier tube. If I want reduced headroom and more sag, I use a 5U4GB.
And there you have it: You’re on your way to becoming a Fender guru, too!
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.
Our columnist is a Fender die-hard but finds thrills in an inspired modern alternative: the Victoria Victorilux.
I am extremely loyal to vintage Fender amps. I love their clean and transparent tones, and how their simplicity makes for amplifiers that are not only collectable but serviceable. I do play other guitars and amps besides Fenders, although I have to admit that I always measure them against the brand and often try dialing them to a sound as close as possible to Fender tone. But this month I want to share a story about a Fender-inspired amp that I love: the Victoria Victorilux.
Victoria has had great success with their point-to-point-wired amps based on classic designs—with a twist. Their long customer list of influential musicians and weekend players proves they’ve done something right. Who doesn’t want a new, robust, high-quality amp that looks and sounds vintage?
My love of the Victorilux started in 2011, when I got to try one for the first time. It was my brother’s, and he showed me a long email thread with company founder Mark Baier discussing different speaker and tube options. I was impressed. My brother’s amp was a 3x10 combo loaded with Jensen P10R speakers. It had dual 6L6GC power tubes and a 230V power transformer. Other speaker configurations were also offered by the company including 2x10, 2x12, and 1x15. Today, Victoria offers Eminence speakers instead of Jensens, according to the company’s website. I really like Eminence Legend 1058 10s and Legend 1518 15s because of their full tone and ability to handle high power without losing touch-sensitivity.
I describe the Victorilux as a Fender-black-panel-style amp in a tweed enclosure with brown-panel charm.
I describe the Victorilux as a Fender-black-panel-style amp in a tweed enclosure with brown-panel charm. As with Fender tweed amps, the chassis is placed vertically in the cabinet, which is robustly constructed with finger-jointed solid pine. The speaker baffle board is Baltic plywood. The controls consist of two 1/4" inputs, volume, treble, mid, bass, reverb, and speed and intensity for the tremolo. With just a single channel, there are fewer things that can fail. The circuit component layout is tidy and takes no shortcuts, and everything is coupled and fitted tightly.
For me, the Victorilux was love at first sight. And that deepened when I heard it. I expected the amp to sound something like a Super Reverb: good and clean. But I was surprised by how fine it sounded at low volumes. It had a sparkling clean-yet-lush-and-warm voice even at the quietest bedroom levels. The EQ spectrum seemed wider than I was used to with older Fender amps—especially for the mid control. I have seen a few Victoriluxes without mid knobs, and I strongly recommend trying one with mid control, since that dial can change the amp’s character between a mid-based British voice and an American scooped tone. With the mid knob set high, the Victorilux starts breaking up surprisingly soon for a dual 6L6GC amp. Lowering the mids will take you back into Fender-black-panel land.
At that first meeting, I was quickly able to dial in a nice tone—as can be done with a vintage Fender. But when I turned up the volume, it didn’t sound Fender black-panel at all. The amp broke up earlier and was more aggressive, with more sag and compression—thanks to the Victorilux’s cathode bias design, which reduces clean headroom. I guess Baier was inspired by the early breakup characteristics of small Fender tweed amps when he chose cathode bias for the relatively high-powered Victorilux. Cathode bias is a less efficient power-amp design compared to fixed bias. All black-panel-era amps and the bigger tweed amps had fixed bias, to maximize clean headroom.
The original Jensen speakers in this amp have been replaced with a trio of Webers for a more powerful and chunky sound, with firm, well-defined bass response.
I also expected the reverb to be lush, but I particularly liked the smooth and gradual knob response. The tremolo could nicely sweep deep and slow or very fast. To summarize, I found the Victorilux to be a brilliantly designed amp that contains the best inspirations from Fender’s tweed and black-panel eras.
I later tried a set of Weber speakers in the amp: two alnico 10A150s in the bottom row and a 10A125 on top. That made it much more powerful and chunky, with firm, well-defined bass response. For those who play in power trios with a loud drummer, I recommend this speaker setup. You will fill the stage completely with massive guitar tone. Those are my favorite Webers, though the ceramic 10F150 or 10F125 will also do the job.
I hope my experience will encourage the vintage Fender fellowship to try out various amp brands. There are ambitious alternatives out there, and my experience with the Victorilux proves that classic tone can be crafted using well-built modern amps.
How our columnist’s risky purchase turned out to be a dusty pre-CBS jewel.
This month, I’d like to share the story of my 1964 Fender Vibrolux Reverb. It was a really risky purchase that had some big surprises.
In October 2011, a black-panel Vibrolux Reverb appeared on eBay with a short bid time. It was poorly described with miserable pictures and barely any details or description of condition and origin. Normally I walk away from such auctions, but there was something that caught my eye. First, some red on the speaker labels led me to believe they were perhaps OEM Jensens. And while the amp’s faceplate was unreadable, I thought I saw a long pattern of four words with a very short last word, as in “Fender Electrical Instruments Co.,” and not the more common “Fender Musical Instruments.” What if this was a 1964–65 pre-CBS amp and no one else recognized it? In the automated eBay watch-and-bid sniper tool I used back then, I set up a $2,500 max bid to be placed 10 seconds before the auction ended. When I woke up the next morning, I had bought it for $1,860. I felt both happiness and regret. What had I gotten into?
When the amp arrived in Oslo several weeks later, I was thrilled to see an all-original 1964 Vibrolux Reverb with Jensen C10N speakers—highly desirable among Fender amp players and collectors. I pulled out the chassis and noticed a well-preserved circuit board, with the death cap wired to the ground switch and a non-grounded two-prong power cord. The brown electrolytic Mallory DC and filter caps looked surprisingly nice and were not leaking. The resistors on the power tube sockets also seemed to be in good shape. It even had factory-original RCA tubes.
When I woke up the next morning, I had bought it for $1,860. I felt both happiness and regret. What had I gotten into?
If you see a leak on a 30-year-old electrolytic capacitor, I strongly recommend replacing it. Old electrolytic caps can mean little clean headroom and farty bass, since they can’t hold the required DC voltage when you strike a chord and the massive current starts flowing through the power circuitry to the tube plates. But I decided to not replace any tubes, caps, or resistors before testing the amp. And the grille? Wow! I don’t think I have ever seen such a dark brown—and nice—piece of cloth, with just minor rifts.
I uninstalled the speakers and noticed the cones were marinated with a thick layer of dirt, dust, and smoke particles, probably from a long life in smoky clubs and bars. I screwed them back on the baffle without cleaning them. The wood was still whole and robust, but the Tolex had many scars and cigarette burns, and the faceplate and knobs indicated heavy but not rough usage. Surprisingly, the pots rotated very smoothly. All this indicates that an amp has been played on a regular basis. It looked like a true warrior.
I found a 230/110V step-down transformer and flipped power and standby on for a 15-second interval. Without proper grounding, I was careful to not touch any other electrical equipment in the room, since you don’t know what voltage guitar strings might carry when connected to a non-grounded amp. I expected the regular background noise—scratchy pots and pop and crackle from bad tubes—but the amp was dead quiet! I stroked a heavy E chord and got a loud, mellow, and very dark and midrange-y tone. I flipped the bright switch on and increased the treble to 5, which is normally an extremely bright setting on Fender amps.
The dusty speaker cones on these old and inefficient speakers filter out the sharp treble—a truly desirable feature in vintage amps. They really make your guitar and pedals sound smoother and creamier, and this was the darkest sounding Fender amp I have ever come upon. What makes the Vibrolux Reverb so good is the balance between the attack and responsiveness of the lightly driven 10" speakers, and the compression from the smaller power and output transformers. I think Fender nailed it with the size, weight, and power of this 35-watt, dual-6L6GC creation.
Later, I installed a grounded power cord and disabled the death cap and ground switch. I got a 230V high-quality power transformer from Mercury Magnetics. It’s 10 years later, and the amp has, incredibly, never failed me. I play it at carefully selected gigs with the original speakers, tubes, and caps still in place. Someday I might consider installing a 25k mid switch or pot on the back in the ground switch slot. This is a must-have and easily reversible mod for Fender amps lacking a mid-pot. It makes them break up much sooner, with a crunch outside the clean Fender tone borderline.
An important point of this story is that we can’t typically expect this kind of luck with vintage amps. Some maintenance is usually required and will make an amp more reliable and durable. Be sure the electrolytic caps are in good condition, and always bring spare tubes to gigs and practices, or bring a backup amp.