Helm Bolt vs Shanling UA1 USB Dongle DAC/Amps Review – Freedom of Choice
In this Article
Summary
These two single-chip dongles (Bolt: ESS9281 Pro, UA1: ESS9218 Pro) are superficially similar but quite different sounding. The Bolt can be summarized as clean and midrange-focused, the UA1 as bass- and upper-mid-emphasized (more “Harman”). Which is preferred will depend on the transducers they’re paired with as well as the tastes (and budget) of the listener.
For this comparison I listened with JVC HA-FDX1 single DD & Ultimate Ears UE900S quad BA earphones to 16/44.1 FLAC files played via USB Audio Player Pro from a Nokia 4.2 Android phone. The Bolt is currently $110, the UA1 $45. For details on physical things, specs, etc., see Jürgen’s individual reviews here and here.
Helm Bolt
In summary, the Bolt’s tonal/timbral package is warm in the bass and more clean & precise in the upper mids & treble. With some material, these contrasting characters make it seem a bit disconnected top to bottom. While having good weight in the bass, bass & sub-bass can come across as a bit boomy, un-defined (one-note) & soft, particularly with the source-picky JVC HA-FDX1.
With the UE900S, though, the tendency for softness in the bass goes away and the rounder character benefits the otherwise lean BA bass notes. Treble is extended but not overemphasized; ‘sweet’ would be the old-school audiophool term. The clean nature of the mids and highs gives a very good sense of instrument separation and imaging.
Overall I found the Bolt to be very good with UE900S – they sound ‘cleaner’ than from other SE dongles I’ve tried them with and the tonal balance benefits their lean-in-the-bass, low-in-the-upper mids, tizzy-up-top character.
Shanling UA1
First impression of the UA1 is of good top-to-bottom integration and good resolution, with dynamics that are more consistent in character across the range. The top end is well defined but well controlled, not splashy. There’s good bass: with HA-FDX1, sub-bass definition & extension are certainly there, both better than with the Bolt.
However, the UA1’s upper mids are a bit nasal/honky/shouty, particularly with the FDX1s which are a bit elevated there. With those ‘phones the UA1 is more balanced at the extremes than the Helm, but a bit tonally and timbrally off in the mids.
With the UE900S, the bass remains good but the upper mids & treble come off as overexaggerated, sibilant and a bit hashy compared to the Bolt. Cable games might help this, but I’m not optimistic.
Matching
Comparing these two dongles with these two earphones shows the importance of synergy: the Helm is a much better driver for the UE900S than the UA1 is. The sweeter treble of the Helm helps balance the 900s’ overdone highs, and although the 900s’ dipped upper mids would ostensibly seem a better fit with the UA1’s tendency for shoutiness, they actually seem cleaner and better balanced there with the Bolt. The Bolt’s softer, rounder bass isn’t a problem, as it makes the 900s sound a bit more natural. With the FDX1s, however, the Bolt gives a very soft sub-bass compared to the UA1. Conversely, while the bass of the UA1 matches the FDX1s better, its Harmanish tonality does their upper mids no favours.
It’s tempting to attribute differences in the bass, in particular, to differences in output power. According to Audio Science Review’s measurements, the Bolt clips at 60 mW into 32 Ohms and about 56 mW into 16 Ohms (HA-FDX1 impedance). Shanling specifies the UA1’s power output as 80 mW into 32 Ohms. The difference between the two dongles isn’t large and I doubt it tells the whole story, because the DragonFly Black is very anemic at 18 mW into 32 Ohms yet the HA-FDX1s don’t lose the definition in the sub-bass when fed from the Black to the extent that they do from the Bolt (warmth of the Black’s signature aside). I conclude that with these dongles, transducer synergy is ‘a thing’.
Other Quick Comparisons
Audioquest Dragonfly Black: pleasant warm emphasis (more than the Bolt), but everything softened and resolution lost (blurred, even a bit scratchy or fuzzy in the highs) compared to the Bolt and UA1. Would view as smooth if not by comparison. Smooth (but not soft) in the bass & lower mids; relaxing with the FDX1s.
Apple dongle: softer than DragonFly Black throughout, not as warm though.
EarMen Sparrow single-ended output: Bolt has better macrodynamics, more and cleaner treble, and is more resolving. UA1 has better note definition (resolution). Sparrow balanced output bests both in dynamics & resolution.
Ifi iDSD Nano BL SE (unfair comparison because: not a dongle, battery powered, 200 mW @ 16 Ohms, significantly more expensive; but included here for completeness because I compared it): darker tonal balance, timbre across the range more integrated, balance between dynamic swings & transient speed more even (maybe a little on the slow side compared to the ESS sound, but to me more natural because of that; organic). S-Balanced is a notable step up over SE in ‘cleanliness’.
Conclusion
It was interesting to hear such different sonic characters from these superficially similar dongles. I hesitate to recommend one over the other as transducer synergy, based on my admittedly limited trials, seems to be important. In general terms, I’d suggest that the Shanling UA1 might be the better match if you have ‘phones that are known to be demanding in the bass; and the Helm Bolt might be the better if you have ‘phones you find at the edge of your tolerance in the upper mids.
Disclaimer
These two dongles were sent to Jürgen for review by Helm Audio and Shanling, who we thank for the opportunity to hear them.
Our generic standard disclaimer.
You find an INDEX of our most relevant technical articles HERE.
