Musical Fidelity Nu-Vista 3D CD player Measurements
I was unable to measure the actual Nu-Vista 3D auditioned by Michael Fremer—it went silent after the review had been written but before the unit was sent to me for measurement. It was shipped back to the UK for diagnosis; apparently, the ribbon cable that connects the transport section to the signal board had gone bad. Musical Fidelity sent me a second sample and I measured that.
The Nu-Vista player's maximum output level (MOL) was 2.113V at 1kHz, a hair above the CD standard of 2.0V RMS. Its output had the correct polarity—the last MF digital product I measured, the X-24K DAC, inverted polarity—and its source impedance was low at 47 ohms across most of the audioband, rising inconsequentially to 78 ohms in the low bass. Assessed with the Pierre Verany Test CD, the 3D's error-correction was superb, the player coping with data dropouts up to 2mm in length without missing a beat. This player won't be fazed by the deliberately inserted lengths of corrupt data that Macrovision's SafeAudio scheme uses to prevent CDs from being ripped on computer drives (see this issue's "Industry Update").
Channel separation (not shown) was better than 100dB across the entire band, and the frequency response (fig.1, lower pair of traces) was mainly flat, though with a very slight, 0.1dB rise in the top octave. However, as seems increasingly common these days, the response with pre-emphasized data (fig.1, top traces) was massively treble-boosted, the 3D apparently either lacking a de-emphasis network or not recognizing the "emphasis" flag in the datastream. Fortunately, almost no CDs these days are pre-emphasized, so this will not necessarily be an issue. Which doesn't mean I like it.
Fig.1 Musical Fidelity Nu-Vista 3D, frequency response at -12dBFS, without emphasis (bottom) and with emphasis (top). (Right channel dashed, 0.5dB/vertical div.)
Spectral analysis of the Musical Fidelity's analog output while it decoded data representing a dithered 1kHz tone at -90dBFS (fig.2) revealed an absence of spuriae and a noise floor dominated in the midrange and above by the 16-bit dither spectrum. However, very small peaks can be seen at 120Hz (both channels) and 60Hz (left channel only), these due to slight electrical and magnetic interferences, respectively, from the player's power supply. These can also be seen in fig.3, a wider-band analysis of the 3D's output while it decoded "digital black"; note, however, the low analog noise floor and the fact that the inevitable rise in ultrasonic noise has been pushed up to over 100kHz in the left channel, and even higher in frequency in the right.
Fig.2 Musical Fidelity Nu-Vista 3D, 1/3-octave spectrum of dithered 1kHz tone at -90dBFS, with noise and spuriae, 16-bit CD data (right channel dashed).
Fig.3 Musical Fidelity Nu-Vista 3D, 1/3-octave spectrum of "digital black," with noise and spuriae, 16-bit CD data (right channel dashed).
Linearity error (fig.4) was therefore superbly low down to below -110dBFS, and, other than a DC offset of around 10µV, the Nu-Vista's reproduction of an undithered 1kHz sinewave at -90.31dBFS was essentially perfect (fig.5). The DAC used by the Nu-Vista 3D—a Burr-Brown PCM1738 chip followed by Antony Michaelson's favored NE5532 dual op-amps as I/V converters or buffers—is obviously a good one!
Fig.4 Musical Fidelity Nu-Vista 3D, left-channel departure from linearity, 16-bit CD data (2dB/vertical div.).
Fig.5 Musical Fidelity Nu-Vista 3D, waveform of undithered 1kHz sinewave at -90.31dBFS, 16-bit CD data.