Tanchjim Fission and Letshuoer S12 Ultra use 1DD and 1Planar (14.8 mm) driver setups respectively. Tanchjim Fission costs $130 while Letshuoer S12 Ultra costs $169. Letshuoer S12 Ultra is $39 more expensive. Letshuoer S12 Ultra holds a clear 0.6-point edge in reviewer scores (6.9 vs 7.6). Letshuoer S12 Ultra has better treble with a 0.6-point edge, Letshuoer S12 Ultra has significantly better dynamics with a 2.4-point edge and Letshuoer S12 Ultra has better soundstage with a 0.6-point edge.
Insights
Metric | Tanchjim Fission | Letshuoer S12 Ultra |
---|---|---|
Bass | 6.9 | 7.8 |
Mids | 7 | 6.8 |
Treble | 7 | 7.6 |
Details | 6.9 | 8.5 |
Soundstage | 7 | 7.6 |
Imaging | 6.9 | 7.9 |
Dynamics | 5 | 7.4 |
Tonality | 7.4 | 7.4 |
Technicalities | 7.3 | 7.3 |
Tanchjim Fission Aggregated Review Score
Average Reviewer Scores
Average Reviewer Score:
6.9Cautiously Favorable
Letshuoer S12 Ultra Aggregated Review Score
Average Reviewer Scores
Average Reviewer Score:
7.6Strongly Favorable
Reviews Comparison
Tanchjim Fission reviewed by Jaytiss
Youtube Video Summary
The Tanchjim Fission presents fantastic value right out of the box, largely thanks to its inclusion of a high-quality USB-C DAC cable with 3.5mm and 4.4mm terminations. The all-metal build feels premium, and the included cable is extremely silky and pleasant to use. A standout feature is the set of interchangeable nozzles that allow for sound tuning; the gold nozzle is the clear winner, providing the best balance, while others can make the bass less impactful. However, the fit can be a challenge for some as the shell lacks a pronounced lip, and the nozzles can be tricky to remove and replace.
Sonically, the Fission is extremely close to the more expensive and beloved Tanchjim Origin, offering a smooth, energetic sound with a tonality that is highly enjoyable. It provides a touch of warmth, pristine detail, and good air, making it a set that is easy to recommend and daily drive. When compared to other sets in its price range, it holds its own against competitors like the Dunu Kima (which has better fit and accessories) and the Kiwi Ears Quintet (which offers more bass), though the choice ultimately comes down to personal preference for tonality and the value placed on its tunable nature.
While it doesn't break the so-called "curse of the $150 IEM," the Fission is a strong contender and gets a full recommendation. Its few cons include a fit that may not work for all ears and a bass quantity that some may wish was greater. For those who value its specific sonic qualities, the excellent build, and the incredible package value with the included DAC cable, the Tanchjim Fission is a fantastic and competitive option that is very easy to enjoy.
Jaytiss Youtube Channel
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Letshuoer S12 Ultra reviewed by Jaytiss
2025-10-05Youtube Video Summary
LETSHUOER S12 Ultra wraps up the S12 line with a 14.8 mm planar driver and a familiar metal shell in gunmetal or mocha. The housing is vented, comfy for long sessions, and solidly built with a flat 2-pin interface that grips tips well. The stock package is practical: a soft case, a fair tip spread, a braided cable with swappable 4.4 mm termination, and even a plug-and-play USB-C DAC that performs capably for on-the-go use.
Sonically, this set aims for a mild V-shape with tasteful tweaks that elevate it over prior S12 iterations. There’s a touch more sub-bass than the S12 Pro and a smoother 10 kHz zone, reducing fatigue while keeping upper-treble reach for air. The presentation favors balance over sparkle: detailed without the brittle edge many planars flirt with, and notably non-fatiguing over longer listens. Technical chops are strong for the class—clean, clear, and “planar-fast”—though instrument separation can lag behind pricier hybrids, and the topmost “crispy” sheen is slightly restrained.
On graphs and in practice, S12 Ultra reads as a refined take on modern planars—more bass weight, tidier 4–6 kHz, and better treble behavior than its siblings. Listeners hypersensitive up top may still prefer something like the S15 for a softer treble contour, while those chasing maximal separation may lean to sets like AFUL Performer 7 (with a spicier treble). With the usual planar caveat about unit variance and fit, this edition comes through as the standout of the S12 series: a clean, engaging, and genuinely high-value recommendation under $500.
Jaytiss Youtube Channel
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Tanchjim Fission reviewed by Web Search

The Tanchjim Fission delivers a notably neutral with vocal-forward presentation in its default configuration, emphasizing clarity and articulation in the midrange without excessive coloration. Bass response is described as clean and firm, offering good texture without bleeding into the mids, while the treble remains smooth and non-fatiguing, contributing to an overall balanced yet engaging listen. Its standout feature is the extensive customization: three swappable nozzle filters (brass for warmth, titanium for brightness, stainless steel for neutrality) and a four-position analog tuning dial collectively enable 12 possible tuning combinations, allowing significant user adjustment to suit genre or preference.
Technically, the Fission leverages Tanchjim’s fifth-generation DMT5 dynamic driver, shared with their higher-end Origin model, which contributes to strong detail retrieval and a surprisingly expansive soundstage for a single-DD IEM at this price. The lightweight CNC-machined aluminum shells ensure comfort during extended use, though isolation can vary and may require tip rolling for an optimal seal. The package includes a practical soft case, a modular silver-plated cable with 3.5mm, 4.4mm, and USB-C (featuring DSP and app-based parametric EQ) terminations, rounding out a strong value proposition at $129.99.
Letshuoer S12 Ultra reviewed by Web Search
2025-10-05
The Letshuoer S12 Ultra continues the brand’s planar lineage with a 14.8 mm planar-magnetic driver in a compact metal shell. Notable upgrades include a 392-core silver-plated cable with interchangeable 3.5/4.4 mm plugs and even a bundled DT01 Pro Type-C DAC cable in some packages, positioning it as a self-contained portable solution at an MSRP around $169.
Tonally, the Ultra aims for a lively U-shaped balance common to prior S12 variants—crisp upper-treble energy with solid bass presence—while early impressions from show-floor demos frame it as the most refined take yet. That aligns with the S12 family’s reputation for strong resolution and a brisk top-end; the original S12 was praised for technical performance albeit with a brighter tilt, context that helps set expectations for the Ultra’s direction.
As with many planars, the S12 line can benefit from competent source power to realize dynamics and control; community reviews note the Ultra responds well to suitable amplification. Staging remains more intimate than expansive compared to some hybrids, but imaging and micro-detail are competitive at the price, making the Ultra a pragmatic sub-$200 pick for listeners who value clarity and transient speed over warmth.
Tanchjim Fission (more reviews)
Tanchjim Fission reviewed by Z-Reviews
Youtube Video Summary
The Tanchjim Fission is an absolutely spectacular IEM that feels and performs far beyond its $129 price tag. It comes loaded with a ridiculous amount of customization, featuring three interchangeable nozzles (stainless steel, titanium, and brass) and a four-way tuning switch, creating a potential 12 different sound combinations. The entire package feels flagship-tier, boasting an excellent interchangeable cable system with 3.5mm, 4.4mm, and USB-C terminations, a waterproof bag, and even a keychain tool for adjustments.
After extensive testing, the definitive "cheat code" for the best sound is using the brass nozzles with the tuning switch set to Pop mode, which seemingly bypasses internal circuitry for a pure, direct sound. This configuration delivers exceptional clarity and a surprisingly wide soundstage, though they are not bass monsters. The fit is excellent, passing the "pinky test," and the build quality on everything from the IEMs themselves to the accessories is exceptional.
While not every combination of nozzles and switches is a winner, the sheer number of options ensures you can find a sound you love. For the price, the value is unmatched, feeling like a product that should cost $279. It comes as a full recommendation, offering a premium, highly tunable experience that is arguably one of the best deals in the IEM market, cementing Tanchjim's reputation for making no bad gear.
Z-Reviews Youtube Channel
Tanchjim Fission reviewed by Jays Audio
Youtube Video Summary
The Tanchjim Fission presents a neutral, balanced, and clean sound signature that is also described as smooth and full. It offers a very natural and laid-back listening experience, making it a strong option for those seeking a safe, non-fatiguing tuning. The technical performance is solid for its price, with good detail retrieval and instrument separation, though it isn't the most dynamic or sparkly set available.
Tip selection is crucial, with recommendations for the Tri Clear or Final E tips to open up the sound, while the Spinfit CP155 can add a touch more bass. The included tuning switches are largely seen as a gimmick; only the middle silver setting is recommended, as the others introduce a significant sub-bass roll-off. The Fission excels with genres like rock, indie, acoustics, and classical at moderate volumes, but its lack of sub-bass rumble and extension makes it a weak choice for hip-hop, EDM, or rap.
Its greatest strength is its value proposition, as it is essentially a cheaper version of the Tanchjim Origin, sharing the same driver and sound profile for a lower cost. This makes competitors like the Moondrop Kato seem less relevant. However, when compared to other all-rounders like the Juzear 4U or Simgot EW300, the Fission faces stiff competition. The EW300, in particular, offers more bass, tuning variety, and similar technicalities for half the price, making the Fission a tougher sell unless its specific brand of smooth, neutral tonality is exactly what you're after.
Jays Audio Youtube Channel
Tanchjim Fission reviewed by Super* Review
2025-09-05Super* Review original ranking
Super* Review Youtube ChannelTanchjim Fission Details
Driver Configuration: 1DD
Tuning Type: Neutral, Vocal-focused
Brand: TANCHJIM Top TANCHJIM IEMs
Price (Msrp): $129.99
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Letshuoer S12 Ultra Details
Driver Configuration: 1Planar (14.8 mm)
Tuning Type: U-Shaped
Brand: Letshuoer Top Letshuoer IEMs
Price (Msrp): $169
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Tanchjim Fission User Review Score
Average User Scores
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Letshuoer S12 Ultra User Review Score
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Tanchjim Fission Gaming Score

Gaming Score & Grade
- The gaming score is prioritizing technical capabilities of the IEM (Separation, Layering, Soundstage) and good value.
Gaming Score
7.4Gaming Grade
A-Letshuoer S12 Ultra Gaming Score

Gaming Score & Grade
- The gaming score is prioritizing technical capabilities of the IEM (Separation, Layering, Soundstage) and good value.
Gaming Score
7.3Gaming Grade
A-Tanchjim Fission Scorings
Average Technical & Tuning Grades
Average Tunign Grade
A-- Pleasing tonal balance with good technical control. Minor quirks present but not distracting. Demonstrates decent genre versatility.
Average Technical Grade
A-- Competent technical presentation. Handles separation and detail well in most tracks, with modest soundstage and acceptable imaging capabilities.
Letshuoer S12 Ultra Scorings
Average Technical & Tuning Grades
Average Tunign Grade
A-- Pleasing tonal balance with good technical control. Minor quirks present but not distracting. Demonstrates decent genre versatility.
Average Technical Grade
A-- Competent technical presentation. Handles separation and detail well in most tracks, with modest soundstage and acceptable imaging capabilities.
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