In the world of digital audio, the end game is the digital to analog converter, or DAC. These small, non-descript microchips are built into a disc player or computer and are the keys to accurately converting the billions of 0s and 1s on a CD or DVD into natural sounding analog signals that are faithful to the original sound. The DAC is the core of digital audio and the rapid improvements in DACs and the rise in popularity of computer audio has driven demand for outboard DACs. These components are designed to upgrade the audio performance of disc players, computers, game consoles and other digital audio sources.
Cambridge Audio DacMagic
The DacMagic is an upsampling outboard DAC offered by Cambridge Audio, a UK manufacturer. Since 1968, Cambridge Audio has offered mid to high-end AV components, accessories and mini systems. The DacMagic is a small component, measuring about 1/3 the size of a mid-sized receiver or DVD player. It can be placed vertically or horizontally using the supplied rubber foot. When connected, the DacMagic performs the digital to analog conversion process usually done in a disc player, a game console, music server or PC. It has inputs for three digital audio sources, two inputs each with coaxial (Toslink) and S/PDIF inputs and a single USB input for connection to the USB audio output of a PC or MAC computer. Analog outputs include unbalanced-line (RCA) and balanced-line (XLR) connections and a digital pass-thru (with Toslink and S/PDIF) is provided to connect a digital audio recorder.
A (Very) Short Lesson in Digital Audio
DacMagic 'upsamples' a digital audio signal from 16-bit/44.1 kHz to 24-bit/192 kHz. Although a full discussion of digital audio is beyond this article, suffice to say that increasing the bit rate from 16 to 24-bits increases the size of each digital sample and upsampling the incoming digital signal from 44.1 kHz (44,100 samples per second) to 192 kHz (192,000 samples per second) increases the quantity of digital pulses sampled per second. The results are greater dynamic range and extended high frequency response of the analog signal output. Another important feature is 32-bit signal processing to reduce signal 'jitter'. Jitter is a digital audio phenomenon related to the timing of the digital pulses, sometimes described as 'shaky pulses'. An accurate digital clock, such as the 32-bit processor helps reduce signal jitter and improves high frequency detail and signal resolution. Other notable features of DacMagic include an incoming sampling rate indicator (32, 44.1, 48, 88.2 and 96 kHz sampling rates) and three digital filters (L) that can be adjusted according to listening preferences. A front panel phase invert switch is provided for digital recording purposes.
Enough with the Science Lessons – Does DacMagic Really Work?
If you're hoping to take your high-end CD player to new performance heights, save your money or invest in another system upgrade. The DacMagic has excellent sound quality, but it probably won't outperform higher-end disc players with DACs optimized for audio performance, unless they are very outdated. On the other hand, many low to mid-priced CD and DVD players cut corners, particularly on the audio side, and here the Cambridge Audio DAC showed some of its magic. The DacMagic didn't do much for my high-end Yamaha CD player, which has always sounded great – no surprise here. Both DACs had excellent resolution, detail and depth. However, differences were more revealing when playing a CD on my (recently purchased) Blu-ray player and an (older) DVD-Audio/SACD player. The differences in sound quality were subtle but nevertheless a reminder that audio quality is sometimes considered secondary, as an afterthought. The DacMagic sounded slightly more open and with greater detail compared to the mediocre DACs in both players. The differences were noticeable, but less significant compared to the improvements when listening to computer audio.
Can DacMagic Elevate the Computer to a Legitimate Audio Source?
The real magic in the DacMagic is listening to computer audio sources. The DACs built into most computers are not known for audio quality unless the soundcards have been upgraded. When connected to the USB output of a PC or MAC computer the DacMagic acts as a digital to analog converter, essentially like an external sound card with high-quality DACs on board. The comparisons were stark. The sound of the DacMagic thoroughly eclipsed the DACs built into my Mac laptop and quickly elevated my computer to a legitimate audio source. With all the music I have stored on my computer, it's like instantly acquiring a new high quality audio source for playback on my system. I store iTunes music in AIFF format, which is CD standard 44.1 kHz, 16-bit audio. It's high quality audio to begin with, but listening through the DacMagic was like lifting a cloak covering the speakers. Clarity and detail improved markedly, with much greater openness and transparency. Connecting the computer is simple. Connect the USB output of a computer to the USB input on the DacMagic, then connect the DacMagic analog output to an analog input on a receiver. The DacMagic comes with no cables, they need to be purchased separately. Beyond computers, the DacMagic offers sonic improvements for other audio devices including music servers, whole house audio systems, Internet radio players, satellite radio programs, video game players, even the digital audio output of a flat panel television. Any digital audio device with optical or coaxial outputs can be connected to the DacMagic and will likely improve sound quality.