Arcam rPAC review
As ever more of us listen to our music collections from our PCs, we're often at the mercy of dodgy on-board audio devices. It's easy to find a sound card for less than £30 that'll improve on most integrated audio, but cheap audio hardware often sounds just that.
This is where DACs come in. While sound cards include Digital to Analogue Converter (DAC) chips, they're also kitted out with Analogue to Digital Converters (ADCs) for audio input, as might be required to record an audio file or chat on a microphone. Many - but not all - also have a dedicated audio processor, while cheaper models will have a single codec (short for coder-decoder) chip which integrates both DAC and ADC, generally at the cost of some audio quality. The most popular dedicated audio processors are made by Creative and C-Media (the latter appear in rebranded form on Asus's Xonar cards) and take the load off your PC when it comes handling features including MIDI processing, gaming audio effects, implementing virtual surround sound or converting stereo audio data into something which can be output by 5.1 surround sound speakers.
These features are all potentially useful to someone, but if all you want to do is listen to high-quality stereo sound and get the most from your music, there's no point in paying for ADCs and dedicated audio processor chips when you could instead buy hardware with a really high-quality DAC. That's where devices like Arcam's rPAC come in.
The rPAC is a tough little metal box with a rubberised base that'll easily sit on the desk next to your PC keyboard or laptop. Its weight means that it's not prone to shifting or being dragged around by any cables you have connected to it. The rPAC connects to your PC via a USB port and has both a 3.5mm stereo headphone output at the front - this has a dedicated headphone amp stage and its own volume controls - and a pair of stereo phono ports at the back, so you can connect the DAC to your amplifier and speakers.
Inside, there's a Texas Instruments (previously Burr-Brown) PCM5102 DAC, RF suppression to cut out interference from common sources such as laptops plugged into unshielded power supplies and an asynchronous USB chip, which maintains its own accurate clock to control the amount of data being passed through it, minimising the chance of (already rare) glitches in your sound.