The Arcam irDAC is a digital-to-analogue converter (DAC) that’s built to serve as both an external sound card for your computer and the digital to analogue stage in a high-end home audio setup. For many audio enthusiasts, it's increasingly important to be able to connect digital sources to a single device and get the same sound quality out of them all. It shouldn’t matter whether the source is the PC on which a digital music collection is stored, a CD player, a digital radio tuner, or even an iPod.

The irDAC comes with a remote control, so you can switch between different inputs. You can also skip, pause and play tracks on a connected iOS device. The volume and mute buttons are standard on Arcam remotes, but they’re redundant in this instance, as the irDAC always outputs sound at line level for output to an amplifier.

The rear of the Arcam irDAC is studded with ports, including two coaxial S/PDIF inputs, two optical S/PDIF inputs, a USB A port and a USB B port. The USB A port allows you to connect an iPod or iPad, while the USB B port is the port you use to connect a computer. The irDAC uses an asynchronous USB connection to eliminate the occasional judders and glitches that can affect devices with adaptive USB connections. The difference between the two is, briefly, that asynchronous hardware has a built-in timing chip that controls how much data is being passed to the audio processor, while a standard adaptive USB connection relies on the computer's clock cycle, a method which is more prone to unexpected variation.

Next to the USB port is a switch that moves the irDAC from USB Class 1 mode to Class 2 mode. Generally speaking, you should use USB Class 2 because this higher-speed connection supports sample rates up to 192KHz rather than the 96KHz maximum sample rate supported by Class 1 mode. However, there are times when you might want to use Class 1, an example being if you simply want to hook up the irDAC to a friend’s PC, as you don't need to install Arcam's proprietary driver to use it in Windows. Whether you've installed the driver or not, Windows users will have to use their operating system's Sound settings to configure the device to use its full bit depth and sample frequency.

Similarly, coaxial S/PDIF connections are a better choice than optical ones, as coaxial connections support sample rates of 192KHz rather than the 96KHz sample rate of the optical S/PDIF connection. The irDAC has a maximum bit depth and sample frequency of 24-bit/192KHz, so you'll ideally want to connect your equipment to make best use of this. In practice there's little difference to be heard between 192KHz and 96KHz, as both are capable of reproducing frequencies well above the range of human hearing, but if you're going to be using high-resolution audio sources it's best to make sure you can play them at their full quality.