The argument of analog vs digital has been quickly coming to a close as digital audio finally begins to reach the quality of what analog had to offer for so long. Now you can get your hands on a number of solid-state amps that move and shake you just like the tube solutions many have grown to love. Given, these will typically run you $1,500 and grow into the tens of thousands, just like some of those nicer tube options (in some cases, more).
Thankfully, the solution we have today is mobile and much more affordable. It won’t offer the quality of those insanely priced options, but it will still offer a reflex within your neck as your head tilts into the effect it brings to what you are listening to.
HELM Audio has had two (THX-certified) mobile amps to offer that released this summer. The first one we recently covered, the HELM DB12 AAAMP. An analog solution with plenty of power behind it and a rechargeable built-in power source. The second solution, a USB-C digital option that we get to cover today– the HELM Audio Bolt.

The Bolt is powered by your phone (or other digital devices) via a USB-C connection and acts as a DAC solution for your music. No built-in battery, which is one of the reasons why it is also quite small. So small, that is not much larger than a short USB-C to 3.5mm aux adapter with no bells or whistles. This means it is quite easy to travel with. It also requires little effort on your part as there are no buttons or anything else for you to worry yourself with. At least, until you get to the process of feeding it, but we will get to that in a moment.

It’s a very simple package, including the DAC/amp, a small USB-C to USB adapter, a nice vinyl (“pleather”) pouch to store it in, and some instructions.
The amp will work in any device with USB-C (or normal USB-A if you use the adapter). This includes mobile devices like smartphones and tablets. It also includes computers and laptops, as well as any OS (Windows. macOS, iOS, Android, etc). You simply need a device that can pass audio through USB. The amp will do everything else.
Once connected, you’ll be able to immediately start playing music to a connected pair of headphones (Windows and macOS will require you to set your speaker/audio-out device to the amp, of course).
As for the before-mentioned exception for steps taken, this lies within the amps support for MQA (Master Quality Authenticated) audio files. It can play MP3 and normal hi-res files (ie, FLAC) just fine and right out of the box. However, MQA is a whole separate beast of its own.
MQA involves lossless music files (many of your lossless file formats are supported) that contain extra (MQA) data within them. This data is decoded by your software or hardware and acts as a way of defining what the audio is supposed to sound like. Delivering the music as the artist originally intended. Something they themselves gave their golden approval for, thus “authenticating” the final format being delivered to the listener. No external EQ or effects to throw it off. Just straight for the source audio. That’s the idea at least.
The only catch is that both your hardware and software have to support this. If you have a standalone mobile player with proprietary functions, then it may be as simple as loading it with MQA formatted files and playing them to whatever headphones or speakers you have plugged in. Of course, those don’t require an external amp as that would already be built into the MQA-supported player. In this case, you are plugging this device in as an external solution for other devices that don’t normally (fully) support MQA output.
This is where software and hardware come into play, this amp being the hardware. So you also need to make sure whatever app is playing your music, also supports MQA so that the information can be unfolded and delivered to the amp, where it will then be decoded (by the amp) and delivered to your headphones (or speakers).
I know that it might sound a little complicated for some, and in many ways, it is if you compare it to normal music listening. However, it isn’t too bad. Again, normal SD and hi-res listening can be had right out of the box. You only have to play around with things if you want to listen to MQA tracks.
That being said, even though “out of the box” performance is possible in many cases, some devices require you to adjust a setting somewhere to enable Hi-Res playback. Many of the Samsung Galaxy phones (for example) make you adjust an option within advanced sound settings to enable hi-res output. This is where you will be able to get the LED on this amp to go from blue to red. Each device can be different. PC’s for another example, you have to go into your audio device’s properties and adjust the default format to as high as your sound card can output. So that brings you to the next step in delivery that this amp can offer you.
As for MQA, you have the hardware, so the software is all you need. Again, you just have to find a solution that can unfold the data and deliver it to your USB amp so that it can do the rest. Else, all you are sending to it is just a FLAC file (which still sounds nice, but isn’t “MQA”). The format is still slowly becoming adopted by companies, so depending on what you have, there may be some waiting till it becomes widely available. For Android, you can use the TIDAL streaming app/service. Specifically, their Tidal Masters hi-res library of music. You can also use an app called “USB Audio Player Pro“, although it does cost $8 to own. Even then, you need a plugin so it will work for MQA.
So this is where there is some work you have to accomplish to get the amp to work properly. Again, this is ONLY if you want to go the route of MQA. Then again, I would assume that is one of the biggest reasons why you’d be giving the amp any attention, to begin with.
Performance
We tend to be a little tough on things like this because we more than lucky when it comes to what we have access to. We have more media and types of formats than you can shake a stick at (although, it’s hard to physically shake a stick at digital information). We have incredibly high-end hardware all over, from players to amps, speakers, headphones, and more. So we have plenty of options to test something with.
That being said, this amp wound up sounding pretty good. At least, for what $99 can get you (price is always important when judging something, after all). It competes within the realm of the Dragonfly amps for both price and performance, which is a great sign for HELM Audio’s reputation and future.
It provides a noticeable boost to any track you feed it. It sounds wonderful when you feed it hi-res formats, and yes, it sounds great when you successfully feed is MQA material.
It will drain the battery of your device a tad faster than normal (ie, smartphone) since that device is powering the amp, but we haven’t seen the effect to be drastic enough to be worried about it (unless your device as terrible battery performance to begin with).
Our Conclusion
It is an incredibly small DAC solution for mobile devices and works well with computers and laptops all the same. The sound it can produce is quite nice and quite noticeable. Regardless of if you are simply looking for some extra dB for your MP3 collection, or looking to take it all the way with MQA source media.
It has a lot of versatility to it. You just have to be willing to take the time to learn how to get it to work fully if you have never played with MQA audio before. So although it looks to be so incredibly user-friendly, this won’t be the case for just any consumer.
It’s small and it’s affordable when you compare it to everything out there, while still sounding good despite this. You can find better, but it will cost you. The world of hi-res and audiophiles does come at a price. Just remember to pair it with headphones or speakers that are also capable of the higher quality sound you are trying to achieve with it.
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Our Rating | Average Price* $99.99 | ||
*Average price is based on the time this article was published
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3 Comments
Ordered mine with $15 dollars off and a free hat. Looking forward to plugging it in.
After 9 months this is a great value for use with my phone!!! Good job Helm!
Received mine yesterday, great little piece of hardware, first impressions let me think that if find it better than my already good Zorloo Ztella (MQA version).