Stereophile – August 2019

stereophile.com n August2019 109

The Sony simply

stepped out of the

way of the music.

SONY DMP-Z1

digital equivalent of analog tone

controls?... which one am I

supposed to like? Most important,

why am I being forced to

choose?”^4 Nevertheless, I spent the

best part of a day auditioning the

Sony’s six reconstruction filters, in the process draining the

DMP-Z1’s battery from fully charged to 19%.

With CD-resolution music—eg, “Satellites,” from Rickie

Lee Jones’s Flying Cowboys (16/44.1 AAC file, Geffen), an

album produced by the late Walter Becker that has superb

dynamic range but can sound a bit forward in the upper

mids—the Short Delay Slow filter gave the most palpable

DAC mode, however. And MQA files played from
the DMP-Z1’s internal storage were identified as
“MQA,” with the unfolded sample rate displayed.
With all files that have a bit depth greater
than 16 or a sample rate higher than
48kHz, including MQA-encoded files,
“HR” (for “Hi-Res”) appeared at the
top of the Sony’s screen, to the right of
the sample rate.
Sony provides a “Guide to High
Quality Sound,” accessible from the
display’s Settings page. The guide
indicates that the DMP-Z1 uses polymer
capacitors and Panasonic POSCAP capacitors in the
amplifier circuit, and that these need 200 hours of
break-in with music playing before they will pro-
duce the “highest quality sound.” I didn’t have the
DMP-Z1 long enough to get to the 200-hour point,
but I noticed no changes in the player’s sound during
the four weeks I listened to it.
I briefly played with the DMP-Z1’s DSP func-
tions, but other than DSD Remastering and the
reconstruction-filter choices, I didn’t spend signifi-
cant time auditioning them. They are what they are. Nor did
I audition the Bluetooth mode—regardless of the conve-
nience, I’m no fan of Bluetooth^3 —other than to check that it
worked with my iPhone 6S. It did.

Listening to filters
As with some other processors and headphone amplifiers
we’ve recently reviewed, the DMP-Z1’s filter options
complicated the auditioning. I echo Herb Reichert’s
question in the May 2019 issue: “Have filters become the

by 1dB at 15kHz, and nulls at 44.1

and 88.2kHz (fig.6, red and magenta

traces).

Channel separation was superb,

at >92dB in both directions from

20Hz to 20kHz. As expected with a

battery-powered device, the DMP-Z1’s

low-frequency noise floor was both

very clean and very low in level (not

shown). Increasing the bit depth from

16 to 24 with a dithered 1kHz tone at

–90dBFS lowered the noise floor by

around 16dB (fig.7), implying resolu-

tion of close to 19 bits. Repeating this

analysis with a dithered 1kHz tone at

–120dBFS gave a superbly clean spec-

trum, with no harmonics visible above

the low noise floor (not shown). With

undithered data representing a tone at

exactly –90.31dBFS (fig.8), the three

DC voltage levels described by the data

were well resolved, with a symmetrical

waveform. A very slight (25μV) DC

offset can be seen in the right channel

(red trace).

Harmonic distortion was very low,

with the second harmonic the highest

in level, at just below –90dB (0.003%,

fig.9), accompanied by the third har-

monic at –106dB (0.0005%). With a

full-scale mix of tones at 19 and 20kHz

and the Sharp and Short Delay Sharp

filters, the noise floor was clean and

Fig.8 Sony DMP-Z1, waveform of undithered 1kHz

sinewave at –90.31dBFS, 16-bit data (left channel

blue, right red).

Fig.9 Sony DMP-Z1, spectrum of 50Hz sinewave,

DC–1kHz, at 0dBFS into 600 ohms (left channel

blue, right red; linear frequency scale).

Fig.10 Sony DMP-Z1, Sharp filter, HF intermodula-

tion spectrum, DC–30kHz, 19+20kHz at 0dBFS into

600 ohms, 44.1kHz data (left channel blue, right

red; linear frequency scale).

3 See stereophile.com/content/arcam-rblink-bluetooth-da-processor-measurements.

4 See https://tinyurl.com/y5aawghn.

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