
Photo 1
Want to reduce the power in an amp with four output tubes? Here’s how to do it right.
Hi Amp Man,
I’ve heard of people pulling one of the two output tubes to reduce the power in a dual-power tube amp. Does this affect the amp’s reliability? Also, if the technique is okay, can you use it on quad output amps like a Fender Twin? And which tubes would you pull? Thanks!
David Lemnah
Hi David,
It seems there’s no shortage of players who want to drop the output power of their amplifier. Some may want to drive their amp’s output stage hard to achieve output-tube distortion, while others may simply find their amp has too much power to even use as a clean platform. Sometimes an amp just sounds better, even when playing it clean, if the output tubes are working a bit harder. This will cause the current flow to increase past the idle current, especially in standard-biased class A/B amps. In my opinion, this makes for a better sounding output tube. Whatever your reason, there is a right way and a wrong way to remove output tubes.
Photo 2
But first, in a standard amplifier with only two output tubes, it’s never okay to remove one output tube. While this would certainly reduce the output power of the amp, two things will happen: It will unbalance the primary side load the tubes place on the transformer, and it will leave one side of the primary completely unloaded. The latter could create excessively high voltage in the winding, and thus cause arcing and transformer damage. Bottom line: Do not remove one output tube in a two-output tube amp. There may be exceptions, such as a single-ended output amp with multiple output tubes in parallel, but I’m sure these are few and far between.
Now, in an amp with four output tubes it is possible to remove two of them, but you need to know which two to remove. Typically amps with a quartet of output tubes have what’s known as a push-pull output stage. (This also applies to amps with dual output tubes.) This basically means that each half of the output stage amplifies one half of the audio signal.
Sometimes an amp just sounds better, even when playing it clean, if the output tubes are working a bit harder.
If two of the output tubes are removed from the same side of the output stage, half of the signal will not be amplified and the sound will be extremely distorted. This will also cause the same issues as removing one tube in a dual-tube amp, so let’s make sure the correct output tubes are removed!
You have a few options: remove the two outside tubes (Photo 1), remove the two inside tubes (Photo 2), remove the first and third (Photo 3), or remove the second and fourth (Photo 4). I prefer any of the last three methods, because each provides a bit more cooling area between the tubes.
Photo 3
After removing the two output tubes, there’s another step that is theoretically necessary, and you should take it if possible. This is to change the output impedance selection to reduce the speaker load by half. For example, if you are running your amp into a 16-ohm load, reduce the impedance selector to 8-ohm. For an 8-ohm load, reduce the impedance selector to 4.
This is more important in Marshall-style amps, as their output transformer design seems to be, or at least is perceived to be, a bit more finicky and vulnerable. Impedance reduction is not an option in amps without impedance selectors, such as early Fender amps, but they seem to be pretty stable and not significantly impacted by this mismatch. In fact, certain amps—such as the Mesa/Boogie Mark Series—feature a “half power” switch that electrically disconnects two output tubes from the output stage with no impedance adjustment and no ill effects.
Photo 4
This tube-removal technique works best in amps that are fixed biased, as opposed to cathode biased. Also, some amps have their output tubes physically arranged in asymmetrical patterns, so consult with the amp manufacturer if possible before removing any tubes. As far as the amp’s reliability, other than the aspects we already addressed, if you occasionally use the amp with all tubes and occasionally with two, consider alternating the tubes you pull so they all wear evenly.
One more point: There are other ways to reduce the volume level of an amp. One is by simply inserting an attenuation device between the amplifier and speaker. THD, Weber, Soldano, Tube Amp Doctor, and other companies make such devices and they function quite well. Another option is to have your tech install a “pentode/triode” switch. This changes the wiring of the output tubes, converting them to a “faux” triode operation. This reduces the amp’s output by approximately 40 percent, which is on par with removing two output tubes.
WARNING: All tube amplifiers contain lethal voltages. The most dangerous voltages are stored in electrolytic capacitors, even after the amp has been unplugged from the wall. Before you touch anything inside the amp chassis, it’s imperative that these capacitors are discharged. If you are unsure of this procedure, consult your local amp tech.
[Updated 12/30/21]
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Leveraging 3D printing technology, the new Floyd Rose Original locking nuts are designed to deliver unmatched precision and consistency, replacing the traditional “lost wax” casting method that dominated for decades.
The shift to 3D printing allows for intricate detailing and tighter tolerances, ensuring each nut meets exact specifications.
The process begins with powdered metal, which is precisely 3D printed into the desired shape using advanced metal printing technology. After printing, the parts are depowdered and cleaned before undergoing a sintering process—an advanced heat treatment—during which the parts achieve full density and hardness. Lastly, the nuts are CNC “kiss-cut” to exacting specifications for consistency and control of the fit before receiving a premium electroplating finish.
“Floyd Rose has always been synonymous with innovation, and by embracing this incredible new technology we are able to continue that legacy,” said Andrew Papiccio, president of AP International Music Supply of which Floyd Rose is a division. “The accuracy and flexibility of the new 3D printing method will allow us to make a more consistent piece while also giving us full control of the manufacturing right here in the USA.”
Initially, the 3D-printed locking nuts will be available in ten classic sizes with a 10” radius, with plans to expand the range to accommodate various fretboard radii in Spring 2025. This augmentation will offer players more options for customizing their setups to match a wide variety of fretboard curvatures.
To get a sneak peek at the new Floyd Rose USA Series, come visit us at NAMM in booth 5734 in Hall D.
With flexible voltage adjustments, precise control, customizable protection, compact design, and affordable pricing at $299, the Brownie is the ultimate solution for optimizing tone and safeguarding your gear.
AmpRx, the trusted name behind the industry-renowned BrownBox, has unveiled its newest innovation: The Brownie, a voltage-optimizing power supply for modern amps and the first of its kind.
Designed by AmpRx co-owner and CEO Cassandra Sotos (2024 NAMM Female Entrepreneur of the Year), the Brownie provides unparalleled control, flexibility, and protection specifically for modern tube amplifiers by allowing the player to both increase and decrease voltage with volt-by-volt precision.
Priced at $299, the Brownie offers an affordable and essential solution for protecting your investment in your high-quality tube amp. It allows you to optimize your tone and safeguard your gear from variations in voltage by givingthe ultimate advantage: knowing exactly what you’re feeding your amp.
Known as the secret weapon of touring professionals, AmpRx products have been spotted on stage with bands like the Red Hot Chili Peppers, Lynyrd Skynyrd, Zac Brown Band, Iron Maiden, and many more. AmpRx is now bringing its game-changing technology to an even broader audience with this compact, affordable, and versatile product. Try the Brownie for yourself and discover exactly why artists, amp designers, and technicians rely on AmpRx to provide consistent sound, performance, and extend the life of their gear.
The Brownie will be available January 20th, 2025, presented at NAMM Global Media Day and on display at Booth #5630.
WHAT MAKES THE BROWNIE SPECIAL? Building on the success of the flagship BrownBox, the Brownie offers key innovations tailored for modern amplifiers:
- Flexible Voltage Adjustments: The Brownie is the first in the AmpRx line to both decrease and increase voltage, providing optimal performance for modern tube amps (often at 117-120V).
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For more information, please visit brownbox.rocks.
Inspecting a D’Angelico Excel during a full restoration.
When every guitar claims to be special, how can any guitar truly stand out?
In the guitar world, a transformation is underway that reminds me of the rise and fall of empires. The modern boutique guitar market, which once felt to me like an underground treasure trove, now seems poised on the precipice. It has grown, matured, and, in my opinion, overextended itself. Are we cresting the wave? Has the boutique boom run its course, or is it simply shedding its skin in metamorphosis?
Guitar building has been around for centuries, mostly as an individual, artisanal endeavor until the late 19th century, when it began to be dominated by manufacturing entities. The boutique guitar category as we know it today began as a reaction to the hegemony of big brands. It was a calling and philosophy—a return to individual builders and small shop manufacturers in the mainstream consciousness. Builders crafted instruments that evoked the patinated romance of vintage instruments as well as the hot-rod aesthetic. What started with a handful of outliers has now become an ecosystem. But, like all trends, there’s a limit to how far it can stretch before it must adapt or collapse.
Pioneers to Proliferation
In the early 1970s, builders like Rick Turner, John Suhr, Michael Gurian, and Bernie Rico, among others, stook as renegades of the modern boutique scene. They were voices bucking the production-line trend with craftsmanship that evoked past masters like D’Angelico, Bigsby, or even Stradivarius. These builders weren’t just producing instruments; they were making statements. A guitar by Parker or a Manzer wasn’t just a tool, it was a declaration of the builder’s ethos and vision—something that might have been lost in the guitar boom of the ’60s.
Today, the boutique world is a crowded stage where hundreds, if not thousands, of builders compete for the attention of an audience with only so much disposable income. Plus, the custom allure is no longer the sole province of artisans; custom shop offerings from major brands like Fender, Gibson, and PRS have blurred the lines. CNC machining and production streamlining have made “boutique” features practical, even necessary, for larger operations. To their credit, unlike at the birth of the vintage market, the big guys saw the wave as well. The once-clear delineation between boutique and mainstream is murkier than ever, which by its nature dilutes everyone’s impact in the segment.
In economic terms, this is a textbook example of market saturation. There are only so many players willing and able to spend $5,000, $10,000, or more on a guitar. Supply has exploded, but demand may be plateauing. Handmade boutique guitars, once a rarefied niche, are now ubiquitous at trade shows, online marketplaces, and across social media feeds. This leads me to a pressing question: When every guitar claims to be special, how can any guitar truly stand out?
The Instagram Paradox
Online, custom guitars have become as much about image as they are about sound. It seems any builder with a board and a butter knife is trolling for your approval. A scroll through Instagram reveals a sea of small-batch instruments, but there’s a creeping sense of déjà vu. How many “offset” guitars with stained burl tops and pre-distressed finishes can one truly appreciate before they begin to blur together? Social media, once a powerful tool for builders to connect with their clientele, has become a double-edged sword. On the one hand, it’s never been easier to showcase work to a global audience. On the other, the sheer volume of content has weakened the impact.
“A guitar by Parker or a Manzer wasn’t just a tool, it was a declaration of the builder’s ethos and vision—something that might have been lost in the guitar boom of the ’60s.”
The Buyer’s Shift
Meanwhile, players too are evolving. With the pandemic-fueled spike in sales fading, some tastes are turning away from the museum-worthy builds in favor of simpler, more traditional guitars. In a way, the legacy brands may now be a salve for the disaffected. In an ironic twist, they are seen as the true foundation of the industry—the original and genuine as opposed to a hip fad.
What Comes Next?
So, has the boutique guitar market peaked? Perhaps. But a peak doesn’t necessarily signal decline. Just as the boutique segment was born from a reaction to mass production, the next wave may be driven by a return to fundamentals. Builders who adapt to a changing landscape or who have built their own legacy will continue to thrive. Those who have not entered the general consciousness may find themselves left behind.
In the end, the boutique guitar market will endure, not because of its size, but because of its soul. Just as guitar building began as an individual endeavor, that heritage will continue. The challenge is to capture the essence of what makes a guitar special in the first place: the connection between builder and player—and the magic of turning wood and wire into music.