Today’s iPhones offer so much technology and functionality packed into a tiny space, it’s getting harder to imagine how the built-in capability can wow us further. Yet British hifi manufacturer Arcam has developed the MusicBOOST; it’s the ultimate accessory to take your iPhone 6 to the next level.

The ‘BOOST offers three benefits; first, it’s a protective case. The stiff plastic shell designed to surround the phone pairs with a rubber-like, grippy material on the case back. The soft surface makes the phone less likely to slip from one’s hand, but the plastic is there to absorb impacts in the event the phone is dropped.

Secondly, Arcam has a battery built-in which trickle-charges its host phone on the fly. Arcam’s specs indicate the battery pack roughly doubles the iPhone 6’s internal battery charge.

Third, and most importantly, Arcam squeezes in a DAC and headphone amp maximizing the prowess of an excellent Burr-Brown chip. Yes, the Arcam can drive larger, efficient headphones when they are connected into the MusicBOOST with an 1/8” adapter. However, it’s not an ideal match for less efficient over the head models, like the infamously tough to drive HiFIMan Phones. The MusicBOOST’s internals are a much better partner for efficient IEMs.

How Arcam squeezes all that capability into a case that adds only ¾” to the length of the phone, ¼” to the thickness, and virtually no width change, is a much appreciated engineering mystery making the MusicBOOST a marvelous, and minimally obtrusive accessory weighing in at only 100 grams. And just like their home hifi and home theater components, they do it at a very reasonable price, $189 in this case.

Setup

The iPhone 6 slides into the MusicBOOST from the top, nesting into a lightning plug at the bottom. Once the phone resides within the case though, external lightning cables can no longer be used. The supplied cord featuring a micro USB connector to charge the phone/case combo takes its place.

The case has only two tiny control buttons. One activates the ‘BOOST’s charger for the phone. The second button gives the user insight into the amount of charge remaining in the Arcam. Depending on the button pressed, four tiny LEDs on the case indicate current status. The rest is plug and play, you can start listening to better sound immediately.

Listening

The iPhone 6’s DAC is not bad, however the Arcam offers an upgrade over the sound quality of the iPhone’s native internals. While Apple Lossless encoding of music stored on the phone offers better resolution than the compressed 256 kb/sec option, both formats benefit from sonic improvement with the Arcam in place. Streaming Tidal’s CD-quality music proves even more revelatory; exposing a bigger gap between the iPhone and the MusicBOOST, now offering a relaxed smoothness that the naked iPhone can’t. The Arcam’s lushness isn’t overly romantic, but it does take music to the warmer end of the spectrum. As a result, vocals and instruments render with detail, but without sharp digital artifacts that detract from the overall musical experience.

Bass also receives a substantial improvement over that produced by the stock iPhone. The combination of an excellent DAC chip for decoding, and the extra oomph from the amplifier, gives low notes a more substantial and weighty presence. There’s simply more low-end information to enjoy. Those enjoying more bass heavy music will dig the MusicBOOST.

Higher piano notes, and the complex frequency combinations ushered forth from a cymbal crash, are portrayed with ample strike and decay. While not rolled-off, the warmer characteristic of the DAC does render higher frequencies with politeness over stridency –  a welcome combination for long listening sessions.

Soundstaging improves through the MusicBOOST too. While the left-to-right soundstage width does not seem to exceed that of the naked iPhone, music enhanced by the Arcam does have a more beguiling overall quality thanks to an increased sense of depth and ambience, giving the illusion of a larger sonic space from around your head.

Is it right for you?

Quibbles with the Arcam are minor. First, the lack of wrap-around phone protection at the top of the case leaves me a bit worried. The back of the case does extend slightly beyond the top of an iPhone 6 offering a good level of drop protection, but there are some areas exposed that would leave an iPhone 6 vulnerable to impact at certain angles. I’ve depended on a Spigen case to defend my iPhone from inadvertent drops, and that solution has saved my bacon many times over. It’s a small leap of faith to count on the Arcam as a primary defense measure for the phone, but the incredible functionality makes it worth the risk.

The second caveat with the Arcam is more a matter of personal preference over practicality. Those who crave the revelation of every tiny, bright nuance in a recording might be disappointed. The MusicBOOST’s warmer sound defers to the bigger-picture forest, and not as much to the individual tree branches. On the other hand, if you prefer a slightly more lush musical portrayal than what your stock iPhone delivers, the MusicBOOST will be just the ticket. Again, a lot of this will be determined by your choice of phones.

At about $200, the Arcam is a small investment, and the functionality packed into it provides lot of value. If one attempted to purchase a high quality case, battery boost, DAC and headphone amp separately as iPhone add-ons, all those individual elements would certainly exceed the Arcam’s price. Plus of course, all the individual components could never match the simple and small form factor the Arcam provides in a single package. After my experience testing the Arcam MusicBOOST, it appears my iPhone 6 has found its new long-term travel partner, and I don’t even have to wrestle our publisher for this one, because he has the larger, 6+.

Publisher’s note: Before handing the MusicBOOST of to Rob, I did put it through its paces with my wife’s iPhone 6S and concur with his assessment. With so many external iPhone amps and DACs now available, I really appreciate the form factor and the convenience of the extra charge capacity; anyone running out of juice near the end of the day on a regular basis will really appreciate another full charge stored in the MusicBOOST.

You wouldn’t think the fraction of a millimeter in thickness between the older iPhone 6 and the newer 6S would mean anything, but it does make the difference between snug and tight. Should you have a newer 6S, plan on making your MusicBOOST a permanent fixture as it is a bit tougher to dock and un-dock. The sound quality is a major step up, especially considering the cost factor, enough so that we happily award the Arcam MusicBOOST an Exceptional Value Award for 2016.

For those just beginning their personal audio journey, this will be a fantastic addition to on the go listening. Even with stock iBuds, the “boost” is very worthwhile. Now if they only made one for the 6S+, I could have one! Come on, come on!

Arcam MusicBOOST

MSRP: $189

www.arcam.co.uk (Manufacturer)

www.soundorg.com (US Distributor)

PERIPHERALS

In-ear monitors: JH Audio JH16, Ultimate Ears UE18, Cardas A8, Sennheiser MM 30i

Headphones: Audeze LCD-X, Sennhesier HD650, Sony MDR-7506

The concept behind a DAC is simple. It follows the same logic related to separating the pre and power stages of an amplifier to improve the latter’s overall sound quality. Isolating a DAC from its sister CD transport and connecting the two via a single cable should, in theory, enable each piece to work at its best as independent units. Such an arrangement eliminates the need of worrying about single-box downsides like electrical cross contamination and other associated distortions.

The technique also yields benefits in that a DAC can serve as a useful upgrade to a trusted CD player. In this setup, the user retains the original CD chassis, utilizes the transport, and plugs in the new DAC, effectively overriding the built-in DAC. In addition, a DAC can also plug into your computer, allowing you to take your PC as a serious digital source—possibly for the very first time. Great multi-taskers, DACs can enhance your audio-visual experience as well. Just attach a DAC to your DVD player or even a set-top box.

Arcam’s new rDAC is one such multi-purpose unit that, in this particular case, is the result of a unique partnership—and one in which a high-quality technological pedigree is instilled within.

“We’ve always had a strong partnership with dCS. Ten or 12 years ago, we built an integrated CD player with dCS, using the company’s Ring DAC technology, blown onto a single chip. We talked to them again about an USB-sourced DAC that dSC had developed. As a result, the rDAC has an asynchronous USB input which allows us to take control of the timing of the USB output of any PC device.”

So says Arcam Senior Engineer Andy Moore, who was tasked to tackle the horror source that is your basic computer. The problem is, your average PC system isn’t optimized for actual digital audio transfer.

“The PC tends to render audio over to the USB input,” confirms Moore, “goes off and does something else, realizes that the memory buffer is starting to run low, and then chucks another load of audio at the USB output—which results in all manner of jitter and timing errors. An asynchronous DAC takes control of it. Like a metronome, the asynchronous DAC says, ‘Give me data: now…now…now…now…’ You’re retiming the output of the PC, thus reducing the jitter errors to a factor of 50 to 100. The goal is to clean the data up before you turn the ones and zeroes into audio.”

Coaxial and optical inputs are also included on the rDAC, but the company recommends that, while fine for CD players and other external fittings, you do not plug your PC into the optical port, as doing so will trigger the return to audio chaos. Internally, the rDAC features a Wolfson WMA741 (the same as the Arcam’s top-of-the-line CD player), multiple staged regulation to provide a clean power supply, and a tidy layout for reduced cross-board interference. The front of the small cast-aluminium and largely inert chassis—spanning just 6.3 x 4 x1.6 inches and weighing only 1.5 pounds— features a row of source lights: USB, Optical, Coax, and Wireless (not actually available on this particular model). A rubberized, non-slip neoprene plate forms the chassis floor and acts as a deadening facility, reducing microphony.

The power supply, a “mere” wall-wart, has a “noise-rejection” supply, designed to reduce distortion. At first glance, this aspect could have been seen to be an obvious weakness to the overall design. But Moore is both re-assuring and slightly dismissive. “As it is, it wouldn’t have improved sound quality with the supply pushed back in the chassis and hooked up to a top quality power cable.”

Lend An Ear

My tests included a range of WAV lossless files ripped using the audiophile-friendly Exact Audio Copy software (www.exactaudiocopy.de). I listened via a Dual Core PC, running Windows Vista, with a trusted pair of Boss MA-12 active speakers. I inserted the rDAC between the MA-12s and the PC, with a USB plugged into the rDAC and the PC.

Playing Steve Jansen & Richard Barbieri’s “Ringing the Bell Backwards” from Stone To Flesh via the Arcam resulted in a dramatic widening of frequency bandwidth. Featured synthesisers, especially those with string emulations, came into true focus while the bass exhibited a newly rounded personality with accompanying power. The soundstage was wider and higher, augmented by a greater degree of instrumental separation that allowed the ear to concentrate on the detail rendered by each instrument.

When auditioning Carol Kidd’s “A Nightingale Sang In Berkeley Square” from Dreamsville, the PC’s midrange sans the rDAC was positively one-dimensional, claustrophobic, and restricted. Turning to the rDAC afforded the vocal performances a more emotional presentation, as acoustic guitar solos became more precise and incisive; cymbal-induced treble traits were now light as a feather. Moreover, the bass had room to move, allowing space to act as a melodic foundation.

Moving to my reference hi-fi and hooking up the well-received budget Cambridge Azur 650C CD player via the coaxial socket made immediately evident the Arcam’s fight against distortion. Although the Azur is a great value performer, the rDAC removed more distortion from the chain, resulting in a relaxed presentation that was easier on the ear—even on overly peak-limited CDs such as the Sugababes’ R&B-oriented Angels With Dirty Faces. Such greater degrees of focus allowed the performances additional chances to showcase their mettle. Bass sounded more natural, and upper mid and treble frequencies proved foot-tappingly musical.

Again and again, the rDAC found the heart and soul of jazz, as on the disc version of the Kidd album. Previously, pianos sounded relatively lifeless. Now, they skipped along like a smooth tap dancer. In addition, acoustic guitar solos had a real metallic edge and vocals served as a reminder that the human voice is made up of multiple parts and tones.

The More the Merrier

As a computer-related DAC, the Arcam box is a no-brainer. Utilizing dCS technology, it transforms USB-sourced data into a quality signal, providing computer users with a whole new sonic perspective. The rDAC also proves worthy in a hi-fi system. Hell, this little box would do wonders for your satellite box and DVD player, too. At this price, it’s a steal. The only question you need to ask is: “How many should I buy?”

Arcam rDAC

$479, €343

www.arcam.co.uk

Peripherals

Digital Source	Cambridge Azure 650C
Preamplifier	Aesthetix Calypso
Amplifiers	Icon MB845 Monoblocks
Speakers	Boss MA-12    Quad ESL-57 (Slightly Modified)
Cables	Avid SCT    Avid ASC