Marantz SA-1 SACD player Measurements part 3
Fig.9 Marantz SA-1, balanced SACD frequency response at Custom (top) and Standard (bottom) settings (right channel dashed, 0.5dB/vertical div.).
DSD encoding also offers greater dynamic range and resolution than CD's 16/44.1kHz LPCM encoding. This is shown in fig.10, the spectra of low-level 1kHz sinewaves at $90dBFS and -120dBFS. The audioband noise floor is significantly lower than it is for CD playback (fig.4), and the tone at -120dBFS can easily be seen above the noise.
Fig.10 Marantz SA-1, 1/3-octave spectrum of dithered 1kHz tone at -90dBFS (top) and at -120dBFS (bottom), with noise and spuriae, DSD data (right channel dashed).
Only when it came to distortion did the SA-1 do anything less than superbly on SACD playback. Fig.11, for example, shows the spectrum of a full-scale 1kHz tone, where some higher-order odd harmonics can be seen. These are still low in level, however, and might well be from the test disc. (Note that the higher noise floor in this graph is due to the Audio Precision System One's internal A/D converters.)
Fig.11 Marantz SA-1, spectrum of 1kHz sinewave, DC-22kHz, at 0dBFS into 100k ohms, DSD data (linear frequency scale).
To assess a player's jitter, I play a test CD-R with a high-level 11.025kHz tone to which has been added the LSB toggling on and off at 229Hz. I then perform a narrowband FFT analysis. Sony's test SACD doesn't have this test signal, but does include a DSD-encoded 11.025kHz tone at 0dBFS. Fig.12 shows the spectrum of the player's output as it decodes these data.
Fig.12 Marantz SA-1, high-resolution jitter spectrum of analog output signal (11.025kHz at 0dBFS, DSD data). Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz.
The only jitter sidebands present are at ±120Hz (dark blue "3" markers) and ±16Hz (purple "1" markers), while the noise floor is superbly low in level. I suspect that the ±120Hz sidebands are encoded on the disc, as they are not present on a similar spectrum taken while the SA-1 decoded diagnostic CD data (fig.13). The highest-level jitter sidebands are now data-related (red markers), though other sidebands can be seen at ±15Hz (purple "1") and ±336Hz (purple "3"). The absolute jitter level was 149 picoseconds p-p, one of the lowest I have measured.
Fig.13 Marantz SA-1, high-resolution jitter spectrum of analog output signal (11.025kHz at -6dBFS with LSB toggled at 229Hz, CD data). Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz. (Grayed-out trace is that from fig.12.)
The SA-1 offers state-of-the-art CD playback, while its analog section is low enough in noise and high enough in linearity to allow much of what DSD has to offer to emerge unscathed from its output jacks.—John Atkinson