If you talk to enough people about the HIFIMAN Susvara, you’ll find that there are two camps of listeners. On the one side are those who say that the Susvara is perfect with any number of high powered headphone amps, and on the other side, those who say that you’re not really getting the full Susvara experience unless you’ve got it plugged into a speaker amp. HIFIMAN has, of course, provided an answer which is “neither, but also both” in the EF1000.
EF1000 is a hybrid tube amp purpose-designed for Susvara. It is built in extremely limited quantities using top tier components. EF1000 isn’t simply an assembly of off-the-shelf parts into an ultra powerful headphone amp, it’s the result of Dr. Fang Bien’s collaboration with HiFi wiz Dehua Liu. They worked together with HIFIMAN’s engineering team to create the optimum amplification system to deliver power to the Susvara. Originally released in 2017, around the same time as Susvara’s launch, each unit is individually hand-made and it’s only made available for sale for short windows. This makes EF1000 not just a unique and incredible amp, but one that comes with a level of exclusivity and makes it very difficult to get your hands on – even if you’re ready to part with $15,000 to make it yours.
In terms of the actual design, the EF1000, technically speaking, is a hybrid tube headphone amp with six EHX 6922 tubes for the input stage and a solid state output stage. It has the balanced XLR and single-ended 6.3mm jacks in the front that you would expect from a headphone amp, but this is no conventional headphone amp. With a power supply that will easily be the heaviest item in your system, the way the hardware is designed and the way power is delivered to your headphones is also very much “speaker amp.”
So is this limited edition, massive, hybrid beast the ultimate Susvara amp – or is it something even more?
Build and Design
The EF1000 comes in two pieces, the smaller of the two is the power supply, engineered to provide pure, high voltage, uninterrupted power. The larger piece is the amp itself. These two units arrive in two separate boxes, and inside each of those boxes you’ll find a case that looks like it was design to transport Iron Man's newest suit. The unboxing process was clearly designed with weightlifters in mind, as just removing the cases from the boxes requires no small feat of strength and coordination. Once they’re out of the box, removing the components from the cases takes a good mix or careful consideration and raw strength that might send you to the chiropractor if you’re not careful.
Once you get it unpacked, you can appreciate the build and design here. The amp itself is larger, featuring a sleek front faceplate, and massive heatsink in the back. The controls are simple enough. The power button is found on the power supply, and the amp has a large volume knob and input and output selections. The input selection toggles between the DAC, CD, or AUX inputs on the back. Output toggles between the headphone outputs on the front and the speaker outputs on the back (connected with banana cables or bare wire).
The volume knob can take some getting used to. As you turn it you get a small “bump” and then a tactile “click” which indicates that the volume has gone up/down one notch. It’s difficult to fine tune the volume, but the feeling of the knob also highlights the immense amount of power being held under control by the EF1000. A remote is also provided, with push button controls that have a smoother operation than the volume knob.
In short, the EF1000 is all about power. This device doesn’t command such a high price because of a stylish luxurious design, or for having a buttery smooth space age interface. EF1000 is all about a transparent distortion-free delivery of incredible amounts of power perfectly matched to the Susvara. So the real question is, when you put it all together, how does it sound?
Sound
In our testing around the office, the combination of EF1000’s hybrid tube power, a high-end DAC, and the HIFIMAN Susvara (or in one case the Audeze LCD-5) resulted in the same reaction from everyone: “this is the best thing I’ve ever heard.”
If you've heard the Susvara before, you might have an opinion across somewhere on a spectrum that is largely influenced by what kind of amp you had powering the Susvara. If you've only heard the Susvara from something like a portable source – like a DAP with decent power for most headphones, but not nearly enough for Susvara – it might have sounded underwhelming. You might even have a number of headphones that you think sound better. If you've heard it from a high quality, high power source, you might have a higher opinion of the Susvara, but might feel some weaknesses in the bass or feel that the resolution comes up just a little bit short. EF1000 let's you eliminate all those misgivings for the best possible listening experience with Susvara.
No matter what superlatives I can throw at the combination of the EF1000 and Susvara, it’s hard to actually exaggerate how good it sounds. Combined with a high quality source and DAC, it’s capable of delivering sound that’s so natural and realistic, with such a strong weight to the 3D image, that it feels surreal. Listening to classic rock, you can feel the visceral energy of a live band, while picking out every detail of the tone and nuance of the performance. With folk, it’s as if the guitar is on your lap, and the voice a few feet away telling a story through song. Classical puts you in a concert hall with the orchestra spread out in front of you, while simultaneously in the middle of the orchestra able to hear all the texture and depth to the instruments all around you.
For most of the testing for this review, we listened to the EF1000 with the HIFIMAN Susvara, Audeze LCD-5, and Meze Elite. Of course, the LCD-5 and Elite are worlds more sensitive than the Susvara, and don’t need this level of power, but they derive their own benefits from EF1000. With the Susvara, you really do hear the difference this level of power can make. EF1000 is absolutely the definitive amp for the Susvara. The advanced power delivery system provides consistent slam, dynamics, and incredible headroom and soundstage.
LCD-5 similarly had slam and dynamics head and shoulders above anything else I’ve plugged it into with EF1000. The depth and extension of the bass was clearly enhanced by the EF1000’s power and the presentation of the 3D image was flawless. Elite, which needed the power least of all, felt enhanced all around, with a blend of all the characteristics that made LCD-5 and Susvara shine…just without really getting very far around on the volume wheel.
While we tested it with a number of TOTL headphones, and some different DACs, our core listening was done with the Susvara and the Chord Hugo TT2 and M Scaler. It’s very hard to imagine putting together a more “ultimate” headphone setup.
On the epic progressive/psychedelic rock song “Ancestral” by Steven Wilson, the first thing that strikes you is the immaculate balance between separation and cohesion in the instruments. Each instrument is crisp, clear, and full of texture, able to be picked out of space and analyzed by itself. Yet each is also masterfully blended in the whole, creating a broad, deep, and detailed and ultimately realistic and natural image. While any of the musicians could be brought out and highlighted, Guthrie Govan’s guitar solo at the midpoint is one of the most important moments of the song, and the EF1000 and Susvara combo perfectly captures the intricacy of the playing with the richness of its tone, and ultimately the emotion of the entire performance.
John Coltrane’s “Naima” is a smooth, slow jam, with a groove that’s perfect for kicking back and relaxing at the end of a long day. With the Susvara and EF1000, you can close your eyes and feel yourself two tables back from the stage in a smoky jazz club. The stage is laid out in front of you, with the drums and bass just off to your right, and the piano and trumpet spaced out on the left. Each highlight or solo brings the player just a little bit closer without breaking the structure or weight of the image. The trumpet is smooth, with just the right energy to stand out from the band without feeling sharp or harsh. The bass is round and textured, with all the weight of upright bass being played ten feet away. The crisp attack and the resolution you can feel from the cymbals, heightens the sense of realism and lends towards a feeling of listening to perfection.
Listening to the Los Angeles Philharmonic performance of Holst’s The Planets provides an epic sense of scale and space. Not unlike the Steven Wilson track I mentioned earlier, the separation combined with the sense of cohesion creates a transcendent listening experience, but this time on a much larger scale. You can lean back, and put yourself just a few rows back taking in the whole piece, or focus onto the strings or trumpets – or, heck, even the percussion on “Mars: Bringer of War” – to pick out each note and beat. You can put yourself somewhere in between as well, listening as the violins match the beat of the snare, then move to a counter rhythm, or dig into the interaction between the brass and stringers throughout.
Of course, this doesn’t need to be all about imaging or thorough musical analysis. EF1000 helps Susvara hit you with some deep, and pretty fun, slam. There’s weight and depth to the bass and that “just right” non-fatiguing energy in the highs that makes it perfect for something like progressive house duo Tinlicker’s song “Paradise.” The autotuned vocals, and smooth synths lull you in, and when the bass hits, its thick and deep, burrowing into your brain to put you in a trance. Again, you can dissect and analyze the layers of interconnected melodies and samples, or kick back, bop your head, and get into the groove as the bass bores a hole in between your ears – the choice is yours.
Comparison: iFi Pro iCAN Signature, Burson Soloist 3X GT
If we’re being honest, this isn’t much of a fair fight. The EF1000 costs six times what either of the others do, and, based on size, if they were animals, EF1000 would eat the Pro iCAN for breakfast, and the Soloist GT for lunch. However, it’s good to have a more grounded comparison for what the EF1000 is actually doing.
While each headphone was a little different, starting with the Susvara, the EF1000 gives you that massive sound and incredible sense of space. It’s dynamic and hard hitting. The delivery is so transparent as to be transcendent while the sound is crisp and almost impossibly well defined, while remaining non-fatiguing. iCAN Pro hits you from the other side of the spectrum. Right off the bat it can’t match the width or depth of EF1000’s soundstage, but it does provide a smoother overall output – even in the solid state mode – that provides a sense of warmth and a little bit of extra power in the midbass. The slam isn’t as deep or broad as EF1000’s, and the dynamics feel more compressed.
The Burson Soloist GT takes you back in direction towards the EF1000. In many ways, it’s everything that EF1000 is, just…less. The space and sound are big, just not as big, and the dynamics are fast and tight, just not as fast as EF1000. It’s also lacking that touch of tube magic on the EF1000, as Soloist GT also provides much of the same definition and clarity, but with a slightly stronger tendency towards fatigue in the top end.
Comparing the other headphones, LCD-5 was largely similar in character and performance to Susvara in how it performed on each amp, but highs were more forgiving with the Soloist GT. The Meze Elite is the one where I didn’t find the EF1000 to be absolutely, unarguably definitive. While I felt that the Soloist GT and EF1000 performed similarly by comparison as they did with the Susvara, the higher sensitivity made Soloist GT’s gain options and lower output more of a benefit. And the Pro iCAN ended up having the strongest tonality for my taste. While Elite’s tuning tends more towards detail and refinement than its predecessor Empyrean, it’s still tuned somewhat for musicality over resolution and clarity, and I found Pro iCAN complemented that design stronger than the big, bold, high resolution output of EF1000.
The Bottom Line
While there are many options that can provide excellent performance with the best headphones in the world, and at a much lower price point, the EF1000 is really in a league all its own. This isn’t “gets the job done.” It’s not “bang for your buck.” The HIFIMAN EF1000 is the absolute pinnacle of headphone amp performance, and the perfect complement to the kings of summit-fi headphones.
