In addition to certifying the efficiency of business cinemas and client audio and video merchandise, THX additionally develops new applied sciences and licenses them to varied producers. Among these new applied sciences is the corporate’s ultra-quiet AAA (Achromatic Audio Amplifier) power-amplifier design, which first appeared commercially within the Benchmark AHB2 in 2015.
Two years later, THX launched the second technology of AAA know-how, this time meant for headphone amps. I first heard some prototypes at CanJam SoCal 2017, and I used to be fairly impressed. So, when Helm Audio introduced at CES 2020 that it was implementing AAA know-how in a cell headphone amp, I instantly requested a overview pattern. Once the DB12 AAAmp lastly arrived, it was properly definitely worth the wait.
This overview is a part of TechHive’s protection of the best headphones, the place you’ll discover opinions of competing merchandise, plus a purchaser’s information to the options it’s best to think about when procuring.
Helm DB12 AAAmp function set
The DB12 AAAmp is a small unit measuring 2.8 x 0.9 x 0.5 inches (LxWxH) and weighing solely 1.08 ounces. A 12-inch cable rising from one finish terminates in a 3.5mm TRRS (tip-ring-ring-sleeve) male plug, whereas a 2-inch cable on the different finish terminates in a 3.5mm TRRS feminine jack. Both cables are custom-shielded silver with molded pressure aid.
If your smartphone has a headphone output, simply join it to the DB12 for a definite enchancment in sound high quality in your headphones. If the gadget has no headphone output, you’ll want an adapter.
Essentially, the DB12 is a powered headphone cable. As such, it depends on a bodily connection at each ends. That means the supply gadget should have a headphone output, which many smartphones and different cell gadgets not have. If a tool doesn’t have such an output, you will have an adaptor for it.
The frequency response is specified from 20Hz to 20kHz (+0.01/-0.2 dB) with a 32-ohm load. The full-range achieve is alleged to be +12 dB with an impartial bass enhance of an extra +6 dB for frequencies between 60 and 100Hz. When I requested why the enhance was solely all the way down to 60Hz, I used to be knowledgeable, “The curve isn’t a bell and it’s not super sharp. It’s a shelf, and it does extend down to 20Hz.” I might advocate saying that within the product data. Output energy is rated at 109 mW/channel into 16 ohms and 111 mW/channel into 32 ohms with <0.1% THD (whole harmonic distortion).
Speaking of THD, it will get a lot better at decrease output ranges: 0.0008% (-102 dB) at 10 mW/16 ohms and 5 mW/32 ohms and 0.00035% (-109 dB) at 0.049 mW/10 kohms. Likewise, IMD (intermodulation distortion) is sort of low: 0.03% (-70 dB) at 16 ohms and 0.01% (-80 dB) at 32 ohms and 10 kohms, all measured utilizing the SMPTE commonplace 70Hz + 70kHz.
To obtain such low distortion ranges, the THX AAA amplifier design makes use of a bipolar class-AB output stage with feed-forward error correction to cancel zero-crossing errors. According to THX, this enables the amp to exceed the efficiency of class-A designs with out their low effectivity, poor damping, and excessive energy consumption. It additionally permits lengthy battery life by decreasing bias currents by an element of 10 to 100 with out rising distortion.
THXAs this graph signifies, THX AAA amplifier modules exhibit a lot decrease THD than competing amp modules at totally different quantities of quiescent energy consumption.
The lithium-ion battery offers six to eight hours of play time relying on the amount setting and whether or not or not bass enhance is lively. A USB-C port on one aspect of the unit helps you to join it to a USB energy supply to cost the battery. The specs say “2.5 hours fast charge, traditional charging time longer,” which implies that a USB energy adapter with an output of 9V/1.67A or 5V/2A can cost the gadget from empty to full in 2.5 hours, whereas an atypical charger with 5V/1A output takes about 4 hours.
A sliding energy button on the opposite aspect additionally prompts the bass-boost mode. The heart button on the highest helps you to play/pause and skip to the following or earlier observe, whereas the “+” and “-“ buttons management the amount.
Helm DB12 AAAmp efficiency
My iPhone XS doesn’t have a headphone output, so I used a Lightning-to-headphone adapter with the DB12. As ordinary, I performed tracks from Tidal’s Master library of lossless high-res audio as my take a look at materials. And after all, I used the gorgeous Focal Stellia headphones, reviewed here, to current the absolute best sound high quality to my ears.
I’m all the time wanting to hearken to Jacob Collier, so I began along with his model of “Here Comes the Sun” from Djesse Vol. 2. His unbelievable association contains huge stacked vocals; a visitor vocal by Dodie; guitars, deep bass, and percussion. The DB12 has a lovely, clear, clear sound with glorious stability and delineation. The bass-boost operate works extraordinarily properly, with no congestion or change in tonality, whereas remaining tremendous clear. Bassheads will find it irresistible, although I did most of my listening with out it; I heard loads of bass with the extra impartial stability.
Next up was “Noble Nobles” by bassist and vocalist Esperanza Spaulding, from her album Emily’s D+Evolution, certainly one of my all-time favorites. The DB12 sounded clear and clear, and I might hear deep into the combination. The bass was completely balanced with out bass enhance, and her vocals had been chic.
For a little bit of nation, I listened to “Sheryl Crow” from Tim McGraw’s album Here on Earth. Actually, this observe has a robust rock element with a dense combine, which sounded fantastic on the DB12. Despite the density, I might hear deep into the combination with super-clean vocals and guitars.
Being a jazz-rock trombone participant from means again, I all the time recognize horn-based funk, which I acquired in spades from “Basket Case” on Brasstracks’ debut album Golden Ticket. The brass licks, drums, guitar, and organ sounded punchy and clear on the DB12. The bass was a bit diffuse, which might be within the combine, and the DB12’s bass enhance made it worse.
Steely Dan is one other of my all-time favourite teams, so I listened to “West of Hollywood” from Two Against Nature. Donald Fagen’s meticulous consideration to each element is plainly evident on this observe, which sounded improbable on the DB12. As earlier than, I might hear deep into the combination, which nonetheless remained utterly coherent and cohesive. In reality, I might make out the lyrics higher than I can on many playback programs.
Turning to classical, I cued up Schoenberg’s Notturno for Strings and Harp as carried out by Zürcher Kammerorchester, with violin soloist Daniel Hope on the album Belle Époch. The DB12 rendered the fragile strings, harp, and solo violin superbly with glorious stability between the sections.
For a extra forceful choice, I listened to the intro to Mahler’s Symphony No. 8, “Symphony of a Thousand,” as recorded dwell by Münchner Philharmoniker underneath the route of Valery Gergiev. The DB12 sounded clear and clear with a pure rendering of the corridor, and I might simply distinguish every part, the choir, and soloists.
Helm AudioThe DB12 can be utilized with a pc in addition to a cell gadget.
Comparison to the iFi hip-dac and iPhone
In addition to the DB12, I listened to every observe on the iFi hip-dac, reviewed here, and the direct output from the iPhone for comparability. Of course, evaluating the DB12 with the hip-dac is just not fully apples-to-apples—each models exchange the telephone’s amplifier, however the DB12 makes use of the telephone’s inner DAC (digital-to-analog converter), whereas the hip-dac replaces the telephone’s DAC with its personal. Still, these two models are very shut in worth, they usually serve a lot the identical objective—enhancing the wired sound of a supply such because the iPhone—so I cast forward.
Overall, I heard no considerable distinction in sound high quality between the DB12 and the hip-dac; each sounded exceptionally clear. The solely distinction—and it’s extraordinarily minor—was that the hip-dac sounded a hair extra impartial and laid again, whereas the DB12 was only a tad extra punchy. But once more, this distinction was miniscule and simply missed if I had not been paying shut consideration.
There was a barely larger distinction within the bass-boost operate of the 2 models. The hip-dac’s bass enhance sounded only a tiny bit congested and fewer properly outlined, nevertheless it was obvious solely in direct comparability and nothing egregious in any respect.
Helm AudioThe energy change on one aspect additionally prompts the bass-boost operate, with LEDs that point out the unit’s standing. Three buttons on the highest management quantity (“+” and “-“) and play/pause/skip observe. A USB-C port on the opposite aspect permits charging.
As I used to be swapping connections between the DB12 and hip-dac, I seen that the DB12’s quantity controls didn’t work reliably; typically, I needed to unplug and replug the unit into the iPhone to get them to work in any respect. Interestingly, the play/pause button appeared to work on a regular basis. On a associated word, the “+” button had an inclination to stay if I occurred to push the outer a part of the button, and it didn’t change the amount on the telephone. This felt like a difficulty of poor alignment with the outlet within the case, which might be a quality-control drawback.
I additionally in contrast the sound of the DB12 with a direct connection to the iPhone utilizing solely the Lightning-to-headphone adaptor. As I had heard throughout my overview of the hip-dac, the direct connection sounded a bit sharper and extra brittle—not tremendously, however barely. And on some tracks, the bass was a bit much less distinct, and the sound was ever-so-slightly congested and veiled, particularly within the low frequencies. This might be due largely to the iPhone’s headphone amp, because the DB12 (utilizing the iPhone DAC) and hip-dac (utilizing its personal DAC) sounded almost an identical.
Bottom line on the Helm DB12 AAAmp
The Helm DB12 AAAmp claims to be the “world’s smallest portable hi-fi headphone amplifier.” I don’t know if it really is the world’s smallest, however it’s remarkably tiny, and it does present distinctive sound high quality. And after all, it’s THX licensed.
My solely actual gripe is that the “+” quantity button typically sticks if pressed within the unsuitable place. Also, the amount controls didn’t work reliably, although that may properly have been as a result of I used to be plugging and unplugging the unit incessantly, which the common person wouldn’t do. And just like the iFi hip-dac, the DB12 doesn’t mechanically energy down after some interval of inactivity, so it’s straightforward to run down the battery for those who neglect to show it off.
Speaking of the hip-dac, it’s sound is just about an identical to the DB12, and it’s $50 much less. It additionally has extra sturdy construct high quality with a super-sturdy energy/quantity knob, and it doesn’t depend on the DAC within the gadget it’s used with. On the opposite hand, it’s bigger and extra awkward to handle with a smartphone.
At just below $200, the DB12 AAAmp is a bit on the expensive aspect, nevertheless it does provide a definite enchancment within the sound high quality of cell gadgets—relying on the standard of their DAC—in a super-convenient bundle.