ES Lab ES-2 alpha (ES-2a) Electrostatic Headphones

<Repost. This review was first posted on the ES2a discussion thread.>

I was an early adopter of ES Lab’s ES1a, which I bought back in mid-October 2020. Fast forward four and a half years, the ES1a is still serving me well—but when ES Lab announced the ES2a, I reached out to Benson Wong over email, and after a few short exchanges, he described the ES2a as a clear step up from the ES1a. That was all the convincing I needed. I ended up purchasing the ES2a at the early-bird price, opting for the brown variant with the default PC-triple-C cables.

In terms of music taste, I wouldn’t say I’m particularly adventurous. I mostly listen to pop, rock, electronic, jazz, R&B, both English and Chinese, the occasional Chinese saliva song (if you know, you know), along with movie soundtracks, musicals, and a bit of classical.

I have a few electrostatic amplifiers in rotation, but for this review, I’ve been primarily using the DIY T2—mainly because it’s what’s currently on my desk. I also briefly switched to the KGSSHV Carbon just to see how the ES2a pairs with a different flavour of amplification. While I do believe in burn-in, I’m not overly obsessive about it. This review reflects my impressions of the ES2a after 2-3 weeks of regular listening, roughly 1–3 hours on most days.

I tend to gravitate toward flagship-level gear, driven by my own standards and, I’ll admit, the classic case of upgrade-itis—something I know many in this hobby can relate to.

Intro
The ES2a enters a crowded and competitive price bracket, populated by everything from upper-mid-tier planar and dynamic driver sub-flagships to electrostatic ex-flagships in the second-hand market. But in this landscape, the ES2a doesn’t just blend in—it stands out with quiet confidence.

Clearly drawing inspiration from the legendary Stax SR-Omega, it pays respectful homage while charting its own path through thoughtful industrial design and refined sonic tuning. It forgoes flashy aesthetics—there are no exposed magnets, no resin-stabilized wood, and no polished carbon fiber shells. Instead, what you get is a headphone that’s subtle in appearance but focused in intent. From the build to the sound, everything about the ES2a feels purposeful, deliberate, and balanced between vintage charm and modern precision.


(this image is taken from ES Lab website)



Build & Design
The ES2a is clearly a passion project brought to life with care. Everything from the packaging to the materials gives it a sense of delicate craftsmanship:

• Leather headstrap and plastic headband work well together—sturdy, not flimsy at all.
• Machined aluminum sliders fit snugly onto the headband, sliding motion is smooth, no play at all. The machined aluminum swivel + forks feel solid and smooth.
• The earpads are concaved, aiding comfort and improving clamping over the ES1a. They are very supple and are apparently crucial in the overall tuning of the ES2a.
• Clamping force is moderate—stronger than ES1a, more relaxed than the SR-Omega. It feels secure on my head.

Design references to the SR-Omega are smartly executed:

• Driver housing is nearly identical in thickness, with a slightly larger diameter (about 2mm larger on the ES2a).
• Classic outer ring design like that on the Omega. Dust protection via metal wire mesh, grids are in upright orientation vs. the Omega's 45° slant. There is no centre rubber stabiliser sandwiched between the inner and outer wire meshes.
• Gun metal coloured flat-head screws used here vs. Omega’s painted crowned screws.
• L/R markings present on front and back of the aluminium sliders—where the Omega’s L/R is backward facing with Omega logo facing the front. Similar to Omega, the L marking is in white and R marking is in red.

The cable is fixed, which might be a downside for some, but:

• The default cable (PC-Triple-C variant) is soft, with minimal microphonics, and has strain relief on both ends.
• It appears to be the same conductor that was used in the ES-R10 cable – according to the information sheet, ES-R10’s cable carries custom-made Triple-C 4 core conductors with layers of vibration-free cladding. The ES2a cable however, is much softer. Perhaps it does not have the vibration free claddings inside.
• There is a low-profile 3D printed Y-splitter bearing the ES Lab brand. It is the same as the Y-splitter on the ES-R10 cable but it does not have the “Made in Hong Kong” label and the brand label is now black and silver instead of black and gold.
• The plug is custom-made, 7cm long—front portion 3D-printed, back portion molded rubber. It’s longer than the original Stax plug (5cm) but feels alright. Connector pins are gold plated, feels sturdy and have no shake or any play. There is a screw in the centre of the plug. I removed it and try to disassemble the plug but the rubber part does not come off easily from the 3D printed part, so I gave up the idea.

Sound Impressions
The ES2a isn’t a "wow-you-in-5-seconds" kind of headphone. It's not trying to impress you with flashy tuning tricks. Instead, it earns your trust gradually—through a deliberate, natural, and non-fatiguing sound that encourages extended listening and deep appreciation.

• Bass:
  Deep and well-extended with a slight roundness. It’s not overly dense or gooey, but well defined and textured, with just enough body to feel grounded without bleeding into the mids.
• Mids:
  Positioned at a comfortable distance—not too forward or recessed. They're highly detailed, yet remain smooth and easygoing in character. The engaging microdynamics deliver immediacy and presence, but I wouldn’t call them intimate—if anything, they’re polite, and some may find them a touch laid-back (in a good way). Timbre is excellent, faithful to the source, and with a hint of warmth.
• Treble:
  Tastefully extended, smooth, and airy. There’s plenty of sparkle and separation without crossing into sibilance or thinness. It doesn’t have the dryness or sharpness some Stax models exhibit, and it remains fatigue-free even during long listening sessions.
• Staging:
  Expansive and spherical, with excellent layering and depth. The stage doesn’t feel artificially wide—there’s no sense of frequency manipulation to create space. It simply sounds naturally spacious and three-dimensional.
• Detail Retrieval:
• Easily on par with the best in the electrostatic world. It’s less edgy than the ES1a or Omega, but still reveals plenty of fine-grained information. You get the resolution without the glare.

The ES2a is offered with two distinct cable options: one utilizing the Stax original pure copper cable, and the other featuring a Furutech PC-triple-C pure copper cable. In my case, my unit comes equipped with the Furutech cable. Given that the cables are hardwired and not user-replaceable, I haven't had the opportunity to compare the two versions directly. I wonder how each cable might influence the ES2a's sound signature and which cable the designer used as the reference during the tuning process.

Anyway, compared to the ES1a (which came with the Stax copper cables), the ES2a is a clear step forward. While the ES1a already impressed with its resolution and tuning, it could sound a little aggressive (honky) in the mids and slightly heavy on the mid-bass. The ES2a tones that down—smoothing out the rough edges, improving coherence, and making the overall tuning feel more mature and articulate. It’s a natural progression and a real step up in terms of refinement and finesse.



Cloth Filters
The ES2a includes detachable cloth filters that line the inner ear-facing side of the driver housing. In my experience, they seem to reduce some energy in the upper mids/lower treble. I prefer listening with the filters in place, as intended by the designer—without them, the ES2a can sound slightly shouty and less cohesive. It’s a subtle change, but enough to shift the overall balance in a way that, to my ears, detracts from the headphone’s otherwise polished signature.

Track-by-Track Notes and Comparisons

Faint – Linkin Park

• ES2a: Vocals are detailed but more relaxed; bass drum has more body and weight than the Omega.
• Omega: Vocals are more upfront and in-your-face. Instrumental – for e.g. the intro is more visceral, almost have a bone scratching characteristics to it, thanks to its rich microdynamics and more upfront mids.
• ES1a: a little edgy and aggressive sounding, bass has less definition than the other two, but definitely very satisfying to listen to.

Check Yes Juliet – We the Kings

• This track may not have the best recording/mastering, it sounds quite congested on lesser headphones/IEMs. So it becomes my litmus test for how tolerant a system is towards bad recordings
• ES2a: Slightly warmer tilt, great cymbal clarity, avoids congestion or shoutiness. I am surprised how well it handles the track, really threw me back to my high school days.
• Omega: More laid-back accompaniment, softer bass. Singer takes the obvious front stage here.
• ES1a: Aggressive mids push forward, a bit of “the honk”, but cymbals less clean.

Doin’ It Right – Daft Punk

• A pair of headphone should not be judged based on its performance at specific frequency range – one might as well just stare at the frequency response curve. But come on, don’t we just love a meaty bassline to sink our teeth into? This track is all about THICCC BASS – 0:27, 0:37, 0:59, 1:20, 1:31 just to list a few
• ES2a: it slaps so hard I’m thrown into another dimension. The bass has excellent depth and a looser, sub-bass feel. The vibe is relaxed, sinfully enjoyable.
• Omega: Tighter, more controlled bass. More of a critical listening kind of feel.
• ES1a: More bass volume, but less definition and less textured.
• I definitely prefer the ES2a for this kind of tracks. When driven with a proper amplifier, the ES2a has the “weight” and slam akin to that in large planar drivers.

Giorgio by Moroder – Daft Punk

• This is an interesting track with a super long monologue at the start, followed by a complex retro-futuristic synth-pop instrumental
• ES2a: Narrative feels intimate, with almost exaggerated details that reminds me of ASMR.
• Omega: More neutral in the mids, more “bland”
• ES1a: Less engaging, not as spacious or detailed compared to either two

Desperado – Emi Fujita

• ES2a: while the vocals sound more blended into the accompaniment, overall presentation is warm, vivid and full of emotion. Really love it.
• Omega: More clinical presentation, more details in the characteristics of the vocals texture

The Power of Love – Celine Dion

• ES2a: spherical soundstage, slightly taller than the Omega. However, the multiple elements in the music are well positioned within the soundstage and it does not feel hollow at all.
• Omega: wide soundstage with prominence on the female vocal, less bass, but again, highlights the singer’s vocal timbre
• Close call between the two headphones, but hey, why choose when I own both.

Ghost of Tom Joad (Live) – Springsteen & Morello - Madison Square Garden, NYC – 2009

• ES2a: Feels like a studio capture, every element of the music are well presented especially the vocal and guitar stand out beautifully.
• Omega: More even and "live", everything blends naturally, nothing is exaggerated and really fights for the centrestage
• ES1a: Flatter and less engaging in this context.
• The Omega is a winner here for sure.

Hotel California (MTV Live) – Eagles

• Omega: Best at reproducing the live concert vibe.
• ES2a: Kick drum has better groove and body, vocals feel a little smoothed out or dithered.

Dvorak Symphony No. 9 – Allegro

• ES2a: wide and tall and diffuse sound stage. Slightly better separation than ES1a. But feels slightly smoothed out.
• Omega: Slightly smaller stage but with more textured instrument timbre. Prefer the Omega for this.

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ES2a With the KGSSHV Carbon

Surprisingly—or perhaps not—the ES2a shows excellent synergy with the KGSSHV Carbon. The Carbon’s relatively neutral and uncoloured presentation complements the luscious and delicate signature of the ES2a beautifully, resulting in a sound that feels natural, balanced, and richly detailed.

When paired with the Carbon, the ES2a takes on a slightly more restrained mid-bass, sounding snappier and more controlled without losing that satisfying sub-bass rumble. The mids remain refined, just as they are with the T2, though they lose a bit of the tubey coloration I know my T2 imparts—especially from its input tubes. What you get instead is a cleaner, more linear tonality, trading some macrodynamics and spaciousness for a more effortless, grounded presentation. Honestly, the ES2a + Carbon combo gives the legendary Omega + T2 pairing a serious run for its money.



In terms of personal preference: Omega + T2 > ES2a + Carbon > ES2a + T2 > Omega + Carbon
(The last combo, to me, is just too sterile.)

That said, the DIY T2 and original Omega aren’t exactly accessible targets for most electrostat enthusiasts. Both are rare, expensive, and finicky. In that context, the ES2a + Carbon might just be the best value-for-money summit-fi electrostatic setup available today—a genuinely endgame experience without the usual pain of chasing unicorns.

Final Thoughts

The ES-Lab ES2a is a clear evolution over the ES1a—improved comfort, more refined tuning, and a build that balances aesthetic homage with functional intent. Sonically, it’s a top-tier headphone that holds its own against the SR-Omega, which is no small feat. It’s honestly hard to wrap my head around how ES Lab has managed to develop such a mature, well-engineered product—especially the driver unit—with limited financial and manpower resources, all while avoiding the fate that nearly befell Stax decades ago.

And here’s the thing: in today’s audiophile landscape, where prices are skyrocketing without regulation, it’s becoming increasingly unclear whether we’re paying for real, tangible improvements, or for marketing hype, "proprietary" tech buzzwords, or pseudo-scientific jargon. The ES2a is a breath of fresh air—no gimmicks, no ego, just substance and sonic excellence. It delivers real value at its price point, and in doing so, offers a legitimate challenge to the industry giants. Audiophiles should rejoice. Bigger players should feel uncomfortable.

To my knowledge, ES Lab operates without distributors or flashy marketing, and that likely contributes to how Benson is able to keep the retail price of the ES2a in check. It’s still a small-scale operation, and its products cater to a relatively niche segment of audiophiles—those who know exactly what they want, and what matters in a headphone system. As one of those people, I sincerely hope ES Lab stays grounded, continues to innovate, and never loses that clarity of purpose.

I haven’t had the chance to hear the EX1a, but I’m glad they’ve released a more affordable model instead of yet another co-flagship to muddy the waters. It’s a welcome move in a market that needs more substance and competition, not more confusion.

In summary, if you're looking in the $2K+ range and want something that truly feels worth your money, the ES2a deserves your attention.

Cheers!