DACs

Cambridge Audio DacMagic

ARTICLE INDEX

The Design

Most hi-fi components are designed at rack width, about 17", so they will stack or fit into an equipment rack. If you look inside some of these components, there is a PC board in one corner and a lot of wasted space.

The DacMagic is designed as an accessory that can be placed anywhere because it is relatively small. I placed the review unit on top of my CD player and the Squeezebox receiver on top of the DacMagic.

cambridge-audio-dac-magic-with-squeezebox-duet

To the left is the power on/off push button, an input selector button, and a filter/phase button which selects the filters. You can select three filters: Lin (Linear), Min (Minimum), and Steep. Linear phase has low ripple and is time coherent, but its impulse response has some pre-ringing. Minimum phase has lower ripple than Linear, and no pre-ringing, but some time coherency is lost. The Steep phase has a very steep attenuation just outside the pass band, so it blocks aliasing at 22 kHz by 80 dB, but it does have pre- and post-ringing. So, in other words, you have choices, each with its advantages and disadvantages. Most outboard DACs don't have these choices. You can also invert the absolute phase by pressing the Filter/Phase button for two seconds. When the Phase LED lights up, the phase is inverted.

Dual stereo Wolfson DAC chips are used, resulting in a fully differential (balanced) circuit. This reduces noise and distortion.

The unit will accept digital signals up to 96 kHz, 24 bit. The input sampling frequency is displayed on six small LEDs at the right hand side of the front panel. They indicate 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz.

The rear panel has plenty of connections: there are two digial inputs that have the choice of RCA or Toslink, a USB input, and a set of XLR balanced and RCA unbalanced outputs.