Sony SCD-C333ES SACD/CD player Measurements

Sidebar 3: Measurements

I have an admission to make: I have never used a carousel player of any kind. But to be able to load up the tray of the Sony SCD-C333ES with all the test CDs, CD-Rs, and one test SACD was such a boon while taking measurements that I began to muse on the possibility of Mark Levinson, Krell, or Wadia producing a carousel transport...nah, won't happen.

Getting the basics out of the way: The Sony's maximum output level at 1kHz was a hair under the "Red Book" standard, at 1.946V (CD) and 1.949V (SACD). It preserved absolute polarity, and the source impedance was a low 20 ohms at middle and high frequencies, rising insignificantly to 30 ohms in the bass. Error correction was superb; the Sony, like the Philips SACD1000 player (also reviewed in this issue), did not skip until track 34 of the Pierre Verany Test CD, which has 2mm gaps in its data spiral.

With the Variable Coefficient Filter set to its STD position for CD playback, frequency response was flat within the audioband, whether with de-emphasis (fig.1, lowest traces) or without (upper traces). Looking at the four Slow Rolloff settings, the Type 1 filter rolled off the highs prematurely, reaching -2.7dB at 20kHz. Filter 3 looks identical to STD in the amplitude domain, except that it starts to roll off above 17kHz rather than extending flat to 20kHz. Filters 2 and 4 are perhaps the most interesting in that in addition to the response shaping, they actually reduce the overall level by a very audible 0.3dB and 0.4dB, respectively. Filter 2 features a slight peak in the presence region before rolling off the top octave. Filter 4 features both a degree of passband ripple and a slight boost in the top two octaves, with then the same small degree of top-end rolloff as Filter 3.

Fig.1 Sony SCD-C333ES, CD data, filter set to Type 1, frequency response at -12dBFS, without emphasis (top) and with emphasis (bottom). (Right channel dashed, 0.5dB/vertical div.)

The Sony's manual suggests that the four slow-rolloff filters have impulse responses with less pre- and post-ringing than the usual sharp-rolloff type. Accordingly, I looked at the impulse response with the filter set to STD; this (fig.2) is typical of a sharp-rolloff FIR filter, with symmetrical "ringing" apparent. By contrast, the impulse response with the filter set to Type 2 (fig.3) has just one half-cycle of pre- and post-ringing, very similar to Wadia's Digimaster filter. The downside of this excellent behavior in the time domain is that the low-pass behavior is "leaky," in that it allows ultrasonic digital images of the audio data to contaminate the analog output signal. The 'scope trace of a 1kHz sinewave with the Type 2 filter, for example, was noticeably furry looking.

Fig.2 Sony SCD-C333ES, CD data, filter set to STD, impulse response.

Fig.3 Sony SCD-C333ES, CD data, filter set to Type 2, impulse response.

The Variable Coefficient filters apply only to CD playback, not to SACD playback. So there is only one frequency response graph for SACD playback (fig.4), taken with Sony's "tentative" test SACD. This has a very slight peaking evident at 30kHz, before a relatively steep rolloff above 40kHz. Interchannel crosstalk (fig.5), also assessed with the "tentative" disc, was buried beneath the noise floor in the midrange and below, rising above the nominal audioband to a still excellent -80dB at 80kHz.

Fig.4 Sony SCD-C333ES, SACD data, frequency response at -3dBFS (right channel dashed, 2dB/vertical div.).

Fig.5 Sony SCD-C333ES, SACD data, channel separation ref. 0dBFS: L-R (top), R-L (bottom). (10dB/vertical div.)

Fig.6 shows spectral analyses of the Sony's output while decoding both CD and SACD data representing a dithered 1kHz tone at -90dBFS. There is little difference in the noise floors in the midrange, and the SACD is actually a little worse in the bass, due to the presence of some spurious but still very-low-level tones at 42Hz, 80Hz, and 140Hz. In the low treble, the SACD offers almost 10dB greater dynamic range, but the rising floor due to DSD's aggressive noiseshaping degrades the SACD dynamic range to less than that of CD above 11kHz.

Fig.6 Sony SCD-C333ES, 1/3-octave spectrum of dithered 1kHz tone at -90dBFS, with noise and spuriae, 16-bit CD data (top below 11kHz) and DSD SACD data (bottom below 11kHz). (Right channel dashed.)

The effect of this noiseshaping can also be seen in fig.7, which compares wideband spectral analyses of the 'C333's noise floor while it plays a CD encoded with "digital black" (bottom traces), and while playing an SACD encoded with a dithered 1kHz tone at -160dBFS! A massive rise in ultrasonic energy can be seen in the Sony's output when playing the SACD, which lead to instability or intermodulation with some amplifiers possessing only limited gain/bandwidth products. However, unlike with the Philips SACD1000 player, this noise does roll off above 100kHz, which should minimize such dangers.

Fig.7 Sony SCD-C333ES, 1/3-octave spectrum of "digital black" (16-bit CD data) with noise and spuriae (bottom above 5kHz), and of dithered 1kHz tone at -160dBFS (DSD SACD data, top above 5kHz). (Right channel dashed.)

The SCD-C333ES's linearity error (fig.8) was low down to -110dBFS, though some noise can be seen in this graph. As a result, the player's representation of an undithered PCM 16-bit/1kHz sinewave at -90.31dBFS (fig.9) is a little noisier than we usually see these days from the quietest designs, though the three discrete voltage levels can still be easily discerned. The DSD-encoded equivalent (fig.10) actually has a good sinewave shape.

Fig.8 Sony SCD-C333ES, left-channel departure from linearity, 16-bit CD data (2dB/vertical div.).

Fig.9 Sony SCD-C333ES, waveform of undithered 1kHz sinewave at -90.31dBFS, 16-bit CD data.

Fig.10 Sony SCD-C333ES, waveform of dithered 1kHz sinewave at -90dBFS, DSD SACD data.

Harmonic (fig.11) and intermodulation (fig.12) distortions were very low in level, even into the demanding 600 ohm "torture" load. However, with the slow-rolloff CD-replay filter used for this test, some spurious images of the high-frequency test tones can be seen at the far right of the graph.

Fig.11 Sony SCD-C333ES, CD data, spectrum of 50Hz sinewave, DC-1kHz, at 0dBFS into 600 ohms (linear frequency scale).

Fig.12 Sony SCD-C333ES, CD data, HF intermodulation spectrum, DC-24kHz, 19+20kHz at 0dBFS into 100k ohms (linear frequency scale).

Finally, because the Sony uses a dual-wavelength laser pickup, it can play CD-Rs, which meant that I could examine its word-clock jitter with the Miller Audio Research Analyzer. (The analytic test signal used for this test is stored on a CD-R with inherently low time-base error.) The Sony performed superbly well on this test, generating just 167.5 picoseconds of word-clock jitter with this worst-case signal. Fig.13 shows the spectrum of the 'C333's analog output for 3.5kHz on either side of the 11.025kHz fundamental. Data-related jitter sidebands (indicated with red numeric markers) all lie below -120dBFS, which is excellent, while the only other sidebands of any consequence are of unknown origin and occur at ±14Hz (purple "1") and ±500Hz (purple "3").

Fig.13 Sony SCD-C333ES, CD data, 44.1kHz sampling, high-resolution jitter spectrum of analog output signal (11.025kHz at -6dBFS with LSB toggled at 229Hz). Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz.

This is excellent measured performance, especially considering the price of the SCD-C333.—John Atkinson

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