Arcam's new MusicBOOST is two products in one, really. It's a battery pack case for the iPhone 6 (or 6s, at a squeeze, which we'll come to), as well as a headphone amp and digital-to-analog converter for your music.
The idea is to bypass the slightly ropey sound components of your expensive Apple phone and use the Lightning connector to feed the audio data directly into the MusicBOOST's DAC and then out to your headphones via the amp component.
Stick your iPhone in (it connects via the Lightning port), then plug your headphones into it, and it aims to make your music sound better.
As an iPhone battery pack, it's fine. It claims to supply 120% of an iPhone charge – we measured a 95% charge (over the course of about two hours), but while lightly using the phone, so you'll certainly get one full charge from it.
You can charge the case (and your phone, while it's in it) using micro-USB. But you can buy battery cases that do this for much less money.
No, it's the music part that might make you buy this.
The idea is that the iPhone's digital-to-analog converter chip is okay, but a better one should offer more precise audio reproduction, allowing for more faithful playback of lossless music especially – and the amplifier supports high-end headphones the iPhone couldn't on its own.
With high-resolution audio starting to become a more mainstream commodity, and higher quality headphones gaining more traction - thanks Dr. Dre - people are starting to take their audio hardware and source material much more seriously.
So, is the effect worth it?
We'd have to say: not really. We listened with different headphones – ranging from around the £150 mark up to the £1,000+ Oppo PM-1s – to both lossless music (in the Apple Lossless format) and standard tracks from iTunes and Apple Music.
And while we could discern a difference, we were really listening, and testing for it in optimal conditions, we just didn't feel like we were missing out without it.
You do hear a bit of extra punch in the bass and percussion, and there's a tad more richness and warmth to the overall sound – but the difference is minimal, and only discernible in some songs.
If you're someone who cares about wringing every possible drop of sound quality out, though, then you might be happy with that improvement. And if you were already considering a separate mobile DAC/headphone amp to go with your iPhone 6 or 6s then also having that battery pack functionality might seem worth the ticket price.
Our bigger issue though was that the case is incredibly tight on the 6s – getting it off is an ordeal. The first MusicBOOST has been specifically designed for the iPhone 6, to be fair, but it is meant to be compatible with the 6s too.
We've been told it relaxes over time (which seemed to start happening for us), but we'd rather have one that was specifically designed to cope with its extra girth.
However, while the case's soft-touch matt material is very pleasant and well finished, it's a bit too slippery for us, and it's not really that protective as a full case.
It also stops in-line mics and controls working on headphones as they're not going directly into the phone itself anymore.
The combination of DAC, headphone amp and 2800mAH lithium-ion battery pack, makes the MusicBOOST seem like a great deal for the audiophile with an iPhone.
There is a discernable improvement to the sound and it offers support for high-end headphones the iPhone can't power alone.
The actual music boost itself, while detectable, still doesn't really deliver enough of an improvement to the iPhone's audio to make the price of the MusicBOOST itself seem like good value.
It also means your headphones with in-line controls and mic for, y'know, using your phone as a phone, stop working.
The half-case design also feels a little odd too. The finish is nice, but it doesn't really offer that much protection.
The Arcam MusicBOOST Just about does what it sets out to do, offering an iPhone DAC, headphone amp and battery pack in one device. But we still think most people simply won't find it worth the money.