Imagine this: you’re playing your favorite riff, and the rich, warm tone flows effortlessly from your amp. That sound you love? It’s all thanks to the magic happening inside the tubes. Much like how the right fuel keeps a car running smoothly, high-quality tubes are what make your amp perform at its best. Without them, you’re not just missing out on great sound—you’re holding your amp back from reaching its full potential. If you want top-tier performance, you must pay attention to tubes you are using, just as you would the oil going into your car.
Vintage Tubes and Legendary Amps: A Timeless Partnership
What’s interesting about tubes is that, unlike computers, gas engines, and other technologies that improve over time, the best tubes were actually made in the past. Back in the day, when tubes were the leading technology, companies fiercely competed to produce the best ones—whether it was the best sounding, the longest lasting, or the loudest. This competition pushed innovation to its peak, resulting in superior tube quality. That’s why, if you want premium guitar (or HiFi) tubes, you have to look to history! The finest examples of tube craftsmanship are vintage, not modern.
When it comes to iconic guitar amps, a few names like Fender, Vox, and Marshall have earned a permanent place in music history. While we could debate which are the most important, today we’re taking a different approach. We’re going to explore another aspect which makes these amps legendary—their tubes. It’s the guitar amp tubes that give these amps their signature sound, and by focusing on this often-overlooked detail, we’ll see why these amps continue to stand the test of time.
Historically, the 6L6 impact is enormous. Its introduction revolutionized amplifier design, allowing for greater power and clarity, which in turn gave musicians the ability to play louder without losing tonal quality. Before EL34’s, EL84’s, KT66’s, and 6550’s there was the 6L6, the granddaddy power tube.
Renowned for its clear, warm, and open sound, the 6L6 is balanced and rich, offering a round low-end, smooth mids, and crisp highs. This tube excels at producing clean tones that remain articulate at high volumes while delivering a natural, musical breakup when pushed into overdrive. It’s this versatility that makes the 6L6 equally suited for jazz, blues, country, and rock.
The Birth of the 6L6: From Innovation to Perfection
RCA didn’t just make the 6L6—they invented it back in 1936, making it one of the oldest tube models still used today. Year after year, RCA tweaked and improved upon their invention giving birth to the 6L6, 6L6GA, 6L6GB, 6L6WGB, and finally landing at 6L6GC.
It is the RCA 6L6GC black plate variant that became the gold standard for nearly two decades, found in legendary amps like the Fender Twin Reverb, Super, Concert, Bassman, and iconic models from Supro, Danelectro, Gibson, and Valco from roughly 1958 to 1969. Widely considered the finest 6L6 ever made, its impact on guitar tone is undeniable. In just 12 years, we’ll be celebrating its 100th birthday, and this tube is still as essential as ever.
Unfortunate, an NOS pair of RCA 6L6GC black plates, is worth their weight in gold. While well worth it in our opinion, we understand their price does not fit all budgets. The clear second best option is the GE 6L6GC grey plate. These cost substantially less, and will perform nearly as well. If you like to explore and tube roll, there are so many vintage 6L6GC types to explore.
Legendary Brands and Variants for Guitar Amps
Among the iconic British amp brands—Orange, Vox, Marshall, and HiWatt—Mullard tubes were the primary choice for their original designs. While Amperex, Telefunken, and Siemens tubes were also used, most of these legendary amps were built around the distinctive tone of Mullards. This made Mullard a key part of the classic British amp sound.
So no surprise, when it comes to EL34 manufacturers, Mullard (and Telefunken) are the gold standard. Mullard EL34s are praised for their mid centric tone, ideal for guitar amps, while Telefunken EL34s are known for their reliability and smooth sound, perfect for Hi-Fi setups.
Though premium NOS options like Mullard and Telefunken can be expensive, vintage alternatives like Siemens, Amperex, and Matsushita offer excellent performance at a lower cost. Make sure to shop for these brands, before buying modern made guitar tubes, if you are on a budget.
For more on European valves in guitar amps, check out our blogs “The Best Tubes for Marshall Amps” and “The Best Tubes for Vox Amps.”
To be continued…
In Part 1 of “The Most Iconic Guitar Amp Tubes of All Time,” we’ve taken a deep dive into three legendary tubes—the 12AX7, 6L6, and EL34—that have shaped the sound of iconic amps from brands like Marshall, Fender, Vox, and HiWatt. The 12AX7’s high gain is key to the electric guitar’s punchy tone, the 6L6 revolutionized amps with its clarity and power, and the EL34 defined the rich harmonic distortion that fueled classic rock.
Now in 2024, vacuum tubes are made to be cheap and disposable, in countries where workers do not have rights, yet while back in the 50’s and 60’s, cutting edge brands competed to make the best possible valves. That is why, brands like Mullard and Telefunken set the standard for these tubes, and why they are so sought after today.
Now, as we look forward to Part 2, we want to hear from you! Which tubes do you think should make the list? Whether it’s the EL84, 6V6GT, KT66, 6550, or something else, let us know which tubes have shaped your sound and deserve the spotlight in the next chapter of this series!
The 12AX7- The GOAT
No tube has played a more significant role in guitar history than the 12AX7. Nearly every guitar amp features one, and for good reason—they’re absolutely essential. With a gain factor of 100, the 12AX7 is the most powerful preamp tube available, delivering the punchy, piercing sound that defines electric guitars. The first boost to your guitar signal flows through the preamp tubes, and that gritty, edge-of-breakup distortion you love happens when the 12AX7 is pushed to its limits. Don’t believe it? Pull the 12AX7 from your amp and hear the difference. Or swap it for a lower-gain 12AT7 (with a gain factor of 50), and you’ll immediately notice a shift in tone, volume, and harmonic complexity.
When it comes to the ultimate 12AX7 for guitar, nothing compares to the Mullard tubes produced in Great Britain during the 1960s. Icons like The Beatles, Jimi Hendrix, Eric Clapton, and Queen all relied on amps powered by Mullard 12AX7s. These tubes were not just any ordinary components, they represent the pinnacle of technology just 6o years ago.
We’ve explored the 12AX7 in depth in our posts on “The Best Tubes for Marshall Amps,” “The Best Tubes for Fender Amps,” and “The Best 12AX7s Ever Made.” Be sure to check them out to find the perfect 12AX7 for your rig! Generally, we recommend using American tubes for American amps and European tubes for European amps.
The Legacy of the 6L6
Before writing this article, we reached out to our Instagram audience to ask what you thought was the most impactful guitartube ever made. Unsurprisingly, after the 12AX7, the 6L6 came out amongst the top. While it was a close race with the EL34, we all seem to agree that when it comes to guitar amp tubes, the 6L6 is a true icon.
Powering the Sound of Rock and Blues: The EL34
In our recent Instagram poll about the most impactful guitar amp tube, the EL34 emerged as a close contender to the 6L6. While the 6L6 is often heralded as the granddaddy of power tubes, the EL34 has established its own legendary status, particularly in rock and blues contexts.
Developed in the early 1950s, the EL34 was engineered to be a high-performance power tube that could rival the 6L6. Designed for efficient output and versatility, it quickly gained traction among amplifier manufacturers. By the 1960s, brands like Marshall recognized the EL34 for another reason… it’s exceptional distortion characteristics, leading to its adoption in iconic amps that defined the rock sound of the era. This marked a significant shift in how power tubes were utilized in guitar amplification, further solidifying the EL34’s reputation. Amp manufacturers were no longer chasing specifically clean tones.
Renowned for its ability to deliver rich harmonic distortion and a robust tonal profile. The EL34 produces a powerful low-end response, warm mids, and sparkling highs, resulting in a dynamic and expressive sound. When pushed into overdrive, the EL34 breaks up fast, leaving the player with piercing midrange bite that birthed the classic guitar solos of the 60’s and 70’s.
The Most Iconic Guitar Amp Tubes of All Time… Part 1
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