Musical Ecstasy: Size Doesn’t Matter

Posted on by Mike Quinn

In bed, late one night, the woman began to react passionately. She sighed. Moved by an ardent sensuality, she whispered, “This is so good. So much more intense and immediate, more sensitive. Even better than when we were in the living room.”

Swept up by the beauty of the experience, she voiced her enthusiasm in no uncertain terms.

She was describing the sound of a stereo.

“This sounds so real. It seems more alive than what we were hearing in the living room.” The woman effusively catalogued the aural qualities of a three-watt amplifier that was driving a pair of very efficient speakers.

Closeup of the Fi "X" single-ended amplfier

The amplifier in question, a Fi “X”, employs a ‘single-ended” design powered by almost ancient 2A3 triode output tubes. This approach to amplifier topology offers a magical, mystical, easy to detect naturalness, with a coherence and immediacy unheard in most other forms of amplification. Far from the latest digital creation, it is a technology developed in the 1920s, and yet today is considered by many to offer the purest, most convincing musical reproduction available.

As good as the single-ended design sounds, there is one serious consideration, that of absolute power: the amount of wattage the amplifier can produce. A single output device, the electrical component in the amplifier that actually powers the speakers, can do a damn good job, maybe the most incisive job of creating music. However, a single device is just not as powerful, in terms of amplifier watts, as two devices working in tandem. As a result, most amplifiers employ twin output devices—called a push-pull design—because we’ve been sold through crafty advertising that more and more power is a good thing. Bigger is better, right? Mas macho

Actually, as with most things, music is not all about power. What we really want is quality and finesse. More power does not necessarily mean more quality; bigger is NOT necessarily better. Often, elegant simplicity trumps beefy, showy muscle. Two amazing watts of power are always far more musical than one hundred, or five hundred, crappy watts.

Let me explain how this works. In the push-pull design, two output devices attempt to perform the job of a single device by dividing the audio wave—an undulating sine wave which modulates up and down across an imaginary base line—into two pieces, the part above the line and the part below the line.

The Theoretical Operation of Push-Pull Amps and the Reality

Unfortunately, this design approach can be a tricky proposition. To recreate the perfect sound wave, vacuum tubes, the output devices of this discussion, have to be perfectly paired, like identical twins, so that the two halves of that audio wave are seamlessly recombined. But in the physical world, that just ain’t gonna happen. In reality, trying to get two vacuum tubes, organic devices in a constant state of deterioration, to perform identically over time is simply impossible. Push-pull tube amps can sound great, but they may just be leaving something behind.  When you finally hear the magical, ethereal sound possible with single-ended tube amps you will discover that something has been missing.

Why does a single-ended amp sound better? In this type of amplifier—often referred to as a single-ended triode amp or SET because the design usually employs somewhat exotic power tubes called triodes—the final powering of that musical sine wave through the speakers is handled by one, and only one, output device, the power triode. By keeping that sine wave an undivided whole, and not trying to divide the chore of amplification between two different tubes, there is no chance of suffering mismatched tops and bottoms of the sine wave. The sound remains pure and faithful to the original: smooth, sweet, and natural.

How the Single-Ended Amplifier Handles The Musical Waveform

“One tube will always do better work than two,” says Gordon Rankin, founder, designer, and chief scientist at Wavelength Audio ( Rankin, whose company is among the leaders of the single-ended amp category, asserts that, “the least amount of moving parts is going to give the best results in audio. Push-pull has so many things going against it. Trying to get those two tubes working together just never works. Anything that happens in one tube that doesn’t happen in the other affects the sound. One tube, no matter how well it’s matched to the other, will always, always, sound different from the other tube, even after just a few hours of operation.”

Rankin has done his share of spreading this gospel to musicians who routinely, when referencing the sound of his amps, make the same comment, “That’s unbelievable.”

As stated previously, one of the chief characteristics of the single-ended amplifier is the naturalness of the sound.

“Even a mediocre single-ended amp does one thing well, and that is naturalness,” insists Joe Fratus, the high-energy force behind Art Audio (, another primary mover and shaker in the single-ended world. “It’s the closest thing you’ll get to live music,” Fratus expounds, “instruments sound like they do in real life. You can pick out all the nuances in recordings, like the differences between horns, even horns in the same family, or pick out the distinctive voices in a vocal recording.

“The single-ended magic comes in part from the detail and resolution,” Fratus, who is also a former jazz bassist, insists. “With a good SET, you are brought into the performance hall or club, you can actually feel the space. But it is also about dynamics. You get a coherency from the top to bottom I don’t hear from push-pull or transistors. It’s just like in a concert hall, the sound is lifelike whether it’s a soft, delicate triangle or a booming tympani. It’s just magic. And you don’t need to get the volume way up to get that magic.”

Fratus agrees with Rankin that more parts just get in the way. “At Art Audio, our philosophy is to keep things simple. We try to build amps that sound natural, we don’t go out looking for bigger bass, or louder volume. We use simple circuits derived from designs of the late 1920s, but, owing to some modern tweaks in the circuitry, we are better at maxing out the tube’s performance in our designs, we know better how to build the transformers and power supplies for the amp to get the best performance and reliability.

“But adding things to the amp to get more volume is not an option for us,” Fratus says. “Adding more tubes, for example, makes the sound worse. You add noise, change the sound, and add distortion that will take away that naturalness we are striving for. Less really is more in this case.”

Fratus has also spent time converting musicians to the SET fold. He recently spent some time with Arturo Sandoval participating in an interesting demonstration. Sandoval was recorded with several other players and the resulting session played back through a pair of Art Audio amps.

Fratus relates the story: “We said, ‘Sit down and listen for yourself.’ He was late for a gig at the Blue Note, but he didn’t want to leave the demo. After just a few minutes he started talking about getting an Art Audio system for his home. Man, I think we blew him away!

“But it’s always that way,” Fratus goes on. “It’s difficult to convince someone of the difference an SET can make unless they hear it for themselves. But every single time, the musicians we do this for agree that the sound is the best they’ve ever heard, even when we play them their own recordings.”

Wavelength Audio's Gordon Rankin

Gordon Rankin, who built his first single-ended amp in 1988 and has now built well over 1,400 tube amps, including more than 1,050 SETs, explains a bit more about the sheer musicality of the SET. “When I built my first 45 [a type of triode tube] amp, the sound was more like music than anything I’d ever heard before. It was a stellar moment. As a musician myself, I have to say that music played through a single-ended amp just sounds more like real instruments. And through a push-pull amp, it always sounds like music played through an amplifier.”

Rankin, who is also a drummer, plays several other instruments including woodwinds, brass, and a wailing electric guitar (his single-ended guitar amps are becoming a cult favorite in the studio), elaborates on how the SET experience can provide musicians, or just civilian music lovers, with a more rewarding, more complete listening gestalt. “When I talk to drummers, I explain that cymbals don’t sound flat as they do through traditional amps, instead they have more harmonics, they have a richer sound. For guitar, you hear more of the natural sound of the instrument, more details, and even more fret noise. With singers, you can often hear when the singer weaves a bit in front of the microphone. You just hear more of everything.”

I have to agree with both Rankin and Fratus. I have long been a tube devotee, but at the annual Consumer Electronics Show a few years back, I experienced an epiphany which made me a firm believer in the SET devotees’ gospel. The importer of an expensive German push-pull amp was giving me a demonstration of his products. The sound was nice, but nothing spectacular. When he was finished, in a different part of the same room, another manufacturer cranked up the same speakers, but used an SET amp to power them. After hearing only a few seconds of music through the SET-based system, my ears perked up. I knew something special was happening. I was engaged with the music in a way I had not been through nearly four days of auditioning audio gear. It was as though that incredible light emanating from the tomb of Jesus had appeared in the room, the difference was that startling, that apparent.

DeVore Fidelity's Gibbon Super 8 Loudspeaker

The only downside to SETs is their relatively low power. Ranging from as low as a half watt (yes, a half watt) to something like twenty or so watts with certain large triode tubes, these amps require careful speaker matching. It is important to pair them with speakers of greater-than-average efficiency, perhaps nothing lower than 90db efficient, depending on the amp, and on the speaker’s other characteristics. For example, the DeVore Fidelity ( Gibbon Super 8s (reviewed here), rated at 90db efficiency, were capable of creating some very nice music with only three watts of SET power. But this is a tricky matter and you should carefully discuss your particular needs with a qualified dealer to avoid underpowering or, in other ways, mismatching your speakers and amp. A few other speakers to consider might be DeVore Fidelity’s new Orangutan 0/96s; the Zu Audio ( Omens, to be reviewed here very soon; just about any of the offerings from Louis Chochos’s Omega Speaker Systems (; or the Cain & Cain Abby (, just to name a few.

It may be a bit more trouble to match an SET amp with the appropriate speakers, but when it all clicks, it’s musical nirvana!

The Fi "X" Single-Ended Amplifier with 2A3 Tubes

I currently own the quite exotic Fi “X” amplifier ($995, about $1400 with Magnequest transformers) built by Don Garber, and, as described above, the amp that can make a woman moan with pleasure. This little gem is based on the classic 2A3 triode and, when powering the right speakers, creates some absolutely stunning music. Garber is an artist-turned-legendary-SET-amp-designer who has gained cult status in the last 20 years or so. One of his amps might be the “X Factor” you need to start exploring the still esoteric world of single-ended amplification. Don doesn’t have a website, but you can contact him via email: [email protected].

We can’t end this discussion without looking at products from Rankin and Fratus.

Wavelength Audio's Cardinal Single-Ended Amplifier

Rankin’s most successful amp is the Cardinal ($8500/pair), a design based on the most popular power triode for audio, the Western Electric 300B. The Cardinal monoblock amps are a study in simplicity, employing just three tubes for each stereo channel and a handful of parts under the chassis. The less-is-more principal is hard at work with these masterpieces of audio design.

Rated at only about twelve and a half watts, the Cardinals, in spite of their low wattage, create an illusion of live music that is difficult to match, with a naturalness achieved by few other amplifiers. The music simply flows out of the speakers, in the case of this audition, the DeVore Fidelity Super 8s. Regardless of style, from loud, raucous Jimi Hendrix to tender vocal renderings by Holly Cole, the Cardinals do it right, do it effortlessly, and do it engagingly. Once powered up, it is difficult to stop listening to the simply gorgeous music these amps reproduce.

One night I had friends over for some audio system demos and the overwhelming opinion was that the refinement of the Cardinals was far more enjoyable than the somewhat clunkier, but much more powerful, presentation of another pair of tube amps we had on hand. “Put the Cardinals back in the system” was something I heard more than once that night. If you truly love good music and strive for excellence in performance, then consider making a nest for these Cardinals in your living room.

Art Audio's Jota Single-Ended Amplifier

I’ve also had the good fortune of twice auditioning an Art Audio Jota ($12,000) in my home and I have always hated having to return the review samples. The Jota was my introduction to the spellbinding qualities of the SET and holds a special place in my audio heart. It uses the 300BXLS tube, a variant of the classic 300B, which allows the Jota to offer a bit more power, in this case about 20 watts per channel. And those are twenty beefy watts, allowing the Jota compatiblity with a wider range of speakers than lower powered SET amps. With this Art Audio marvel, I’ve had no problem driving any of the speakers that have come through my living room for review, and that’s been a very diverse array indeed. Each and every time, the Jota produced that level of quality and naturalness Fratus aims for and has very certainly achieved. It is the kind of sound that raises goose bumps, that startles, that captivates, and satisfies.

The robustness of the construction combined with the handsome design and the stunning sound make the Jota a worthwhile investment in first-rate audio performance. While auditioning the Jota, I found new life in my LP and CD collections,   discovering details I had never before heard in discs I’d listened to hundreds of times. But this amp’s success transcends those details, those little tidbits. It’s the macro view—the impression of correctness—of real music, that places the Jota in a rarefied circle.

It serves here to reiterate Fratus’s declaration: nothing sounds more like real music than music played through a good single-ended amplifier. For true music lovers wanting to connect more fully with their passion, a system built around a good SET amp deserves consideration. Precious little else approaches the startling realism these singular jewels can produce. Prepare yourself for moans of pleasure and delight as you ignite musical emotions with a single-ended system in your living room…or your bedroom.

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