High-performance audio DAC drives novel CD player

Wolfson's high-performance stereo digital-analogue conversion technology is at the heart of two new CD players introduced by hi-fi specialist Rega Research.

Wolfson's high-performance stereo digital-analogue conversion technology is at the heart of two new CD players introduced by hi-fi specialist Rega Research.

Pure sounds from the Rega Planet 2000 and Jupiter models depend on ICs based on the WM8716 DAC - a multibit, 192kHz stereo DAC employing a novel sigma-delta conversion technique, which ensures optimal signal-noise performance and substantially lower clock jitter effects.

Rega prides itself on making quality hi-fi products at sensible prices, and sells only through specialist dealers rather than mail order, with minimal advertising.

CD players were a new venture for the company, with the first CD player only being introduced in 1997.

Rega enthusiasts prefer the purer analogue sound of vinyl, so its digital audio products have a high quality threshold to beat.

The Planet 2000 employs a single 24bit DAC, improving on the original CD designs based on previous generation convertors.

Higher quality still is available from the new Jupiter model, which has two of the devices, one for each stereo channel.

The Wolfson-developed chip is designated IC40, which Wolfson was able to supply as a custom Rega-branded solution to meet the customer's requirement.

It comprises a three-stage FIR filter followed by a 16x oversampling linear interpolator that significantly reduces high-frequency images compared with the more usual sample-and-hold implementation.

Using a 64-level sigma-delta convertor results in significantly lower errors produced by clock jitter, and this is further improved by the design's switched capacitor implementation of the lowpass filter, which is also insensitive to clock jitter.

Signal/noise ratio is better than 112dB (A weighted at 48kHz), while total harmonic distortion is -97dB at -1dB FS.

The chip additionally features a differential mono output mode, enabling systems such as the Jupiter to boost quality and eliminate crosstalk by using separate DACs for left and right channels.

For both Planet 2000 and Jupiter models, Wolfson supplied the device in small 28-pin SSOP packaging with Rega branding.

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