Arcam rPAC USB DAC/Headphone Amplifier Review

Many people, myself included, use their computer as one of their primary music sources. I myself spend countless nights relaxing in front of my MacBook, digging through my iTunes library rocking out to forgotten favourites. Sure, the sound is nowhere near that of my hi-fi setup – it doesn’t come close, in fact. But it’s convenient.

The problem, however, is the built-in headphone amp found in many computers is an afterthought. Even that built into my Mac, a top of the line Retina MacBook Pro, is a cheap, underpowered afterthought designed to ‘get the job done’. It lacks depth, has a terrible sound – take the music to levels when it can truly be appreciated and the sound becomes a harsh, bright mess.

The solution? Of course, I could stream music to my hi-fi via the mac – but this means powering up a stack of components just for a late night listening session. Plus, the mac needs to be in close proximity to the hi-fi in order to stretch a cable from the DAC to the Mac’s USB port.

No, the solution is simple – a USB headphone amp. These products have recently begun flooding the market, thanks to increasing demand for high quality, high resolution audio. These tiny devices connect to your computer’s USB port, bypassing the inferior DAC and amplification hardware and delivering hi-fi quality sound to your headphones.

Arcam’s rPAC is one such device. This pocket-sized, aluminium clad device contains a 24-bit, 96 KHZ DAC (the Texas Instruments PCM5102), a 138MW headphone amplifier and an Asynchronous USB input. Power is provided by the USB bus, so there’s no external power supply – and there’s a line level output for outputting to a standard hi-fi amplifier.

Unboxing

The packaging is simple and neat. Lifting the lid of the box reveals some documentation and a drawstring velvet case, neatly situated atop a tray containing the rPAC itself and 2 cables. Those cables include a USB A-B cable, and an RCA cable for use when using the rPAC as a DAC in your hi-fi setup.

The rPAC itself is wrapped in a plastic bag to protect the finish. Thanks to its aluminium casing, it’s surprisingly heavy – it feels much heavier than the quoted 300G. The included case is large enough to accommodate the rPAC itself, along with its USB cable – making this a perfect way to achieve high quality sound on the move.

Build quality

As you would expect from Arcam, build quality is rock solid. The thick, substantial casing offers up no resonance when tapped. The bass is fashioned from a rubber material, which prevents the rPAC sliding around on your desk. It does pick up dust, but keep your desk clean and that shouldn’t become a problem.

Even the connectors are high quality – unlike many 3.5” headphone outputs, this one doesn’t flex when pressing a jack in – in fact, jacks slide in and out smoothly with very little force required. The RCA jacks are similarly flex-free, and the USB jack on the device itself is equally solid, so you won’t lose connection if you move your laptop and flex the cable.

The top of the unit features 2 volume buttons which, when pressed offer up a satisfying tactile click. These controls are very responsive, the volume gently raising and lowering as the appropriate button is held. These hardware volume controls are independent of the operating system’s software-based controls – this means you’ll have to experiment to find the optimal balance between the volume of the headphone amp itself and the volume on your computer.

Turn the rPAC up too loud, and the sound becomes harsh – I found roughly half way was the best setting, using my Mac’s volume to make minor adjustments. I’d have preferred the volume be either software or hardware based, and not both.

Sound

Upon hooking up the rPAC, it was instantly recognised by Mac OS X and i could begin using it straight away. Throughout this review, I also noticed the unit does not become hot in operation as is the case with other portable headphone amplifiers.

Right off the bat I was pleasantly surprised to note the extremely low noise floor – so low, , in fact, I struggle to pick it out at all. I noticed when running the headphone amp with its hardware volume control reaching higher levels that there was a slight popping sound when a short sound, such as the mac’s volume change sound or a notification, was played. This isn’t a problem for music (unless the music stops and starts regularly), but could become annoying if you’re using the rPAC as a sound card for gaming.

Like many Arcam products, the rPAC favours a smooth, warm presentation. Playing Halestorm’s ‘Love Bites’, I had the distinct impression that the highs were slightly rolled off – no chance of extraneous brightness here. This is advantageous when playing tracks such as Ozzy Osbourne’s ‘Shot In The Dark’, a track that on many systems suffers from a bright top end.

That smoothness has its downsides, however – the rPAC doesn’t possess the sheer rhythmic ability to keep a track such as ‘Flesh and Bone’ from The Killer’s Battle Born album charging along as it should. It prefers slower, more laid back tracks such as ‘the way it was, or Queen’s ‘Too Much Love Will Kill You’, where the emotion of the tracks take precedence and make up for the lack of rhythm.

Instrument placement is excellent, each instrumental layer given its own sense of space to breathe. Separation of vocal harmonies is another of the rPAC’s strengths, though it struggles splitting those harmonies in Queen’s ‘Bohemian Rhapsody’. Switch to some of Queen’s earlier material, however, such as ‘Good Old Fashioned Lover BOy’ from A Day At The Races, and the rPAC is right at home. The performance is rhythmic, sound stage is excellent, and the bass and drums are perfectly controlled, with a full bodied sound to them. This stunning performance kept me hooked from beginning to end.

Summary

There’s no doubt that the Arcam rPAC is a fine headphone amplifier, with an equally fine DAC. If you frequently travel, or use your computer for late-night music listening where use of the hi-fi isn’t practical, the rPAC will enable you to get the best sound from those iTunes tracks.

It’s significantly larger than some rivals – many rivals being the size of a small USB drive. And it’s not the last word in subtlety or rhythmic ability. But its smooth, likeable character means it gets a firm nod of approval. Highly recommended.