Helm Bolt DAC

I heard about this little USB-C dongle DAC/amp called the Helm Bolt from Michael Lavorgna's website Twittering Machines. He used to write for stereophile and audiostream, I always liked his writing style and alternative taste in music even though I was not always a big fan of the types of products he was pushing.

anyway, Twittering Machines is a breath of fresh air compared to most mainstream audio review sites, and in recent a dongle shootout Michael picked the Helm Bolt as his favorite: https://twitteringmachines.com/the-dongle-dac-survey-part-2-the-reviews/

I was in the market for a dongle but out of the loop on what was good, and didn't really want a generic chi-fi product. the description of the Helm from the shootout seemed up my alley so I ordered one in March and it arrived in April. the price is $99 USD although there is a significant 50% discount for military and healthcare personnel so check that out if you qualify.

In the box is the dongle, a little carry pouch and a USB-C to USB-A adapter for use with computers and laptops. I also got a free hat for pre-ordering in between production batches. the hat is of middling OEM quality. I would not recommend ordering just the hat as a fashion accessory. it will go on top of my leaning tower of hats.



although advertised as a dac/amp it's only capable of driving efficient and low impedance headphones directly. it did not have quite enough volume for my HD600s, resting at about 70 - 75 dB SPL (I am guesstimating this figure) at maxed volume with a recording of average loudness. it does appear to adjust the output voltage based on the impedance of the connected load. I assume this was done to control the gain for earphones versus line sources.

as a DAC/amp

I hooked up the Bolt to my 2008 Mac Pro using the included USB-A adapter, to my iPhone XR using a USB-C to Lightning adapter, and to my modern Windows desktop PC. sound quality was rather crummy from the motherboard of my desktop PC, excellent on my Mac, and in between the two with the iPhone although leaning much closer towards the quality of the Mac. I mention this as YMMV depending on what you USB source you plug the Bolt into.



I used the Bolt to listen to my trusty Koss KPH30 (like a portapro but clearer and more balanced tonally) and new-to-me ESX900 headphones (review here). It really is a sublime sounding dongle, I was kind of dumbfounded by what $99 can get you these days. I have to agree with what Mr. Lavorgna wrote in his dongle shootout about the Bolt - and the words that come to mind to describe its sound are full, rich and sweet. in comparison, the Apple lightning dongle sounds anemic and congested, flatter with less nuance. the Bolt + Koss or ESX900 could be a desert island solution for listening to music while waiting for rescue efforts.

as a DAC

enthused by the results of the Bolt driving headphones directly, I purchased an Audioquest 3.5mm to stereo RCA adapter to use the Bolt as a DAC into my main headphone amplifier. compared to ~$3000 of R2R DAC, the Bolt fought valiantly. it lost in the areas D/S DACs always lose: the transfer of subtle emotions, the transfer of musical flow (timing), and the most honest transfer of musical timbres. the Bolt does have a sort of sweet, sugary timbre, but it's rather subtle and honestly very preferable to AKM for me.



I guess this thing uses an ESS chip, but not sure. however in most other areas, it was very difficult to fault the Bolt as a DAC. maybe I am just out of the loop and all dongles these days including the $20 ones from China sound this good, but I sort of doubt it. I could also list any number of full-sized DACs I have tried from $100 - $3000 that sound worse than the Bolt, but you guys probably wouldn't believe me, so I won't.

in conclusion, buy two of these, one for you and one for a loved one. if you don't have any loved ones, buy one for a stranger and they will love you for it. I think it's very much worth the $99 asking price. I will personally take it any day of the week over the current Modi, unless for some reason you really needed the connectivity options of the Modi. it's also great that the Bolt is MQA certified, meaning that I can preserve the artist's true intention by fully unfolding master quality authenticated source files. unfortunately I don't have a TIDAL premium account, so I wasn't able to test this feature. still, having the MQA logo on my DAC helps me sleep at night.

 

Interesting, I've always find my stock KPH30i being the muffled, treble lacking version of stock porta pro. Did you do any pad changing? I am also trying to get a grasp of the 4levels of music reproduction you mentioned in the ESC900 thread, I guess music genre plays a huge part here?

 

How's the power? These source powered dongles can produce some limp-sounding bass.

 

It’s worth noting that despite the marketing copy saying the DAC support ups to 32/384, anything above 24/96 has to be done by MQA unfold. I don’t care much about audio above 24/96. I have a few 24/192 files and a few streams on Qobuz are 24/192, and I suspect any benefits from hi-res cap out at 24/48 anyway, but it irks me that this otherwise well reviewed DAC is artificially software limited purely for the benefit of a for profit compression scheme that we now know is lossy and introduces errors in the music.

 

I should mention my portapro is a new one.. the old ones sound better and clearer up top. out of the currently shipping Koss models, I found KPH30 to sound clearer and more balanced than portapro or KTXPRO1 (my old favorite but sadly they don't make them like they used to). no pad changes.

it is easier to understand in the context of classical music, as there exists a composer-interpreter relationship, or composer-interpreter-performer if we want to consider the conductor and the soloist/ensemble as separate identities. the 4th level is when the music begins to take on aesthetic meaning or purpose, when the intellectual, sensual and emotional content of music is received by the listeners subconscious. for me, I know when this occurs due to being moved to involuntary physical reactions.

it can be perceived with any genre of music I think - although some might argue that rock and roll is devoid of intellectual content, others might argue electronica is devoid of emotional content, it doesn't really matter. the individual's receptiveness to the meaning of any musical work is just that - individual. science has no explanation for what constitutes this receptiveness, I theorize exposure during developmental years is probably the number one factor, but people develop and advance their musical tastes even in late adulthood.

if the stars align: you have a good recording, a strong relationship or subconscious link between the composer and interpreter/performer, a good system, you are sitting in your favorite chair, the ambient temperature of the room you are sitting in is comfortable, your boss didn't yell at you today - then you can get the sensation of your soul burning when listening to music.

we can also cheat the system by using a recording and performance of the first class - like the one below. only a truly awful system would damage its emotional energy to where the listener is no longer involved in it. either that or the person themselves has to be truly spiritually bankrupt to not appreciate it. in either case - it would be depraved to continue to participate in 'high-end' audio.

maybe it was measured by ASR in their review. I only looked at how the panther was posing before buying.

two things:
1) as I stated there is only enough headroom in terms of volume for very efficient headphones. even on the ESX900, I ran into a handful (<5%) of recordings where the gain was low enough or dynamic range high enough that I wished for an average spl increase in the neighborhood of ~5dB. despite this, dynamics were always satisfactory, especially in the bass.

2) the DAC itself has a bit of a bass-lite signature. I think this may be characteristic of the new generation of ESS? this may be part of why it is so synergistic with the ESX900. it still swings, very convincingly. to quote Michael Lavorgna: 'not the biggest boldest bottom end'. but not limp.

 

This is probably because it's limited to UAC1 more so than shady MQA nonsense. UAC1 capped out at 24/96, and works with older versions of windows without the need for a driver. Not useful nowadays since Windows 10 supports UAC2 just fine.

 

I picked one of these up on sale. Listening on a Pixel 3a to V0 MP3s from Bandcamp. Earphones are HD25s with the Oyaide cable.

Comparing against the Pixel 3a headphone out: It's not often I say things like night and day, but the Helm Bolt is night and day... worse.

Plus points: the Helm has more macrodynamic drive with better articulated sustain and decay, and is clear. Treble is not offensive.

Mildly negative points: tonality is a bit u-shaped, there's a big scoop in the mids and a little too much bass emphasis. Narrow soundstage.

Egregious negative points: this thing is totally dead behind the eyes. No microdynamics at all, flat, cold, uninvolving.

Basically every time I listen to this I can do about half an hour before I can't take any more and go back to the headphone jack. Vs the Helm I lose a bit of bass control but gain a heap of microdynamic nuance and immediacy, better soundstage, and keep the smooth treble. In fact the presentation is pretty similar to the Wavedream but much less refined. Is the Google dongle this good?

 

The differences in impressions seems to be a result of personal preferences. @k4rstar likes the Helm Bolt as well as Abbas DACs, and many in Texas recently expressed their dislike of it. Just wondering out loud ...

 

nope, you heard it wrong

 

Personally, I have a bit of a love/hate relationship with my Bolt. The tonality is sweet and inviting, the resolution is nice, it has a nice overall FR profile with nothing sticking out anywhere, round and well-done.

It doesn’t really do anything wrong, but still—it’s boring.

As analogy, I’d say the Bolt presents music matter-of-factly. Like a well-trained butler that serves you a meal, and every single movement of his is perfect, he is absolutely professional. But you can tell at first glance that he is bored like hell.

That’s the feeling I get from my Bolt. Very good, but a bit lifeless.

 

ASR "reviewed" the 2 versions extant in late 2018 and found output Zs of 1.2 Ohm for V1, 7.6 Ohm for V2. Maybe you have the V2.

Please; interested in listening impressions.

 

Thanks! I just got the latest usb-c dongle to compare with the pixel 3a headphone out. The pixel 3a is similar tuning but a bit more coherent. Less resolution, definitely greyer, but more microdynamic nuance (seems contradictory but that's how it is) and a more even tonal balance - a bit more mid colour and focus, and top end slightly rolled. Definitely more engaging than the dongle. Unless... the $10 dongle needs breaking in?