DAC Chip: Undisclosed (Single) THX,
PCM 32bit–384khz, MQA, DSD256, SNR: -120db, Power: 1-2 Vrms Adaptive, USB Type-C Male, 3.5mm SE (Microphone: NO)



  • Natural balanced timbre, slightly warm with low frequency boost
  • Well rounded and controlled dynamics, great coherence
  • Crisp and smooth Treble with polished decays, great extensions
  • Intimate Mids with rich textures, realistic tonality
  • Thick, punchy, fast Mid-Bass responses, great texture, fast decays
  • Deep Sub-Bass presence, smooth decays
  • Realistic guitars and stringed instruments tone, polished edge
  • Great balance between technical and musical ability
  • Good Macro & Micro details retrieval, very transparent
  • Superb speed and transients, will not get congested or compressed
  • Great resistances to sibilance, forgiving on Lo-Fi recordings
  • Great driving power to drive stubborn planars and earbuds
  • Great resistance to heating even used for long hours
  • Does not drain host battery too fast
  • Synergize well with many type of IEMs/HPs/Earbuds


  • Tall but narrow soundstage, lacking space, somewhat compressed feel
  • Lacking air in the notes compared to the top performers
  • Low frequencies coloration on Mid-Bass section


HELM BOLT. Helm Audio opted not to reveal what DAC chip used in this unit. But my ears telling me this has all the tell-tale of ESS ES9281C MQA which is known to be capable to work with THX. That tall but narrow soundstage is a clear give-away of ES9280-ES9281 signature which I have heard quite frequently (over 15 units of ES928x series I have owned so far)

While overall this is a very clean sounding unit, I must admit I was taken aback by the compressed sense of space within the tall but narrow soundstage. This was quite apparent when paired with the likes of FOSTEX T40RP MK3 and VE ZEN 2.0 SLQ, both of which are very demanding headphone/earbud. Even on easy to drive SeeAudio Bravery & TForce Yuan Li, the BOLT exhibited similar traits. Precisely I felt that the staging was all focused in the middle of my head with instrumentations split left and right – so it is narrow, compressed and lacking holographic imaging. About the only time I felt that the soundstage felt “normal” was when paired with 7Hz Timeless Magnetic Planar IEM. There was proper sense of space and air. But the rest of my IEMs, Earbuds and Headphones all shared the same tall but narrow feel.

Another element that I observed, in the lower register Bass especially Mid-Bass exhibited some coloration which was very evident as revealed by T40RPMK3. The Mid-Bass was a tad thicker than how I heard it from the top performers of #donglemadness. All 5 Star performers exhibited very neutral and natural Bass responses, even the slightly euphonic TempoTec Sonata E44 does not have this Bass coloration despite being the most commanding in Bass control among the top contenders.

On MQA side, BOLT proved to be a great unit with very stable Masters unfolding and free from any element of artifacts as observed with other MQA Dongles. For example some prominent unit may exhibit stutter and jitters when unfolding Masters, but BOLT remained stable and with great fidelity.

HELM BOLT should be commended for being closer to organic and natural sounding (despite the lower region coloration). It is so easy for modern Dongles like this to end up overly bright and metallic sounding as observed with HiBy FC3, Zorloo Ztella and Hidizs S3 Pro. HELM BOLT actually reminded me a lot of Audirect BEAM 2S with that warmer timbre

Finally, being an ESS9280-9281 variant, HELM BOLT does exhibit great fidelity driving very stubborn IEMs/Earbuds/Headphones. I am especially impressed with how sweet my T40RP MK3 sounds like despite having narrow staging. Same goes for 7Hz Timeless. But not as impressive sounding with TForce Yuan Li and SeeAudio Bravery. HELM BOLT however does pair great as well with Shure KSE1500 serving as an AUX Line Out for the Electrostatic IEM, this attributed to HELM BOLT being super clean, the KSA1200 Electrostatic Energizer Amp helped to mitigate any native deficiencies BOLT has.

⭐⭐⭐½ ($100)

Best Pairing: An already wide sounding partners

Back to #donglemadness

Great pairing with 7Hz Timeless Magnetic Planar

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