Stereophile – August 2019

stereophile.com n August2019 107

SONY DMP-Z1

I

measured the Sony DMP-Z1 with

my Audio Precision SYS-2722

system (see the January 2008

“As We See It”^1 ) using test-tone

files copied to the Sony’s internal stor-

age. The DMP-Z1’s battery was fully

charged before I began testing, and I

measured the player’s performance

at its single-ended headphone jack in

Direct Source mode, which bypasses

the DSP functions.

Apple’s USB Prober utility iden-

tified the DMP-Z1 as “PLAYER”

from “Sony” with serial number

“1045A0A1000727” and confirmed

that its USB port operated in the

optimal isochronous asynchronous

mode. Apple’s AudioMIDI utility

revealed that, via USB, the DMP-Z1

accepted 16-, 24-, and 32-bit integer

data sampled at all rates up to 384kHz.

The Sony’s maximum output level at

1kHz was 2.02V in normal mode, 4.0V

in High Gain mode. The output imped-

ance was a low 5.5 ohms from 20Hz to

20kHz. The output preserved absolute

polarity (ie, was noninverting).

I examined the DMP-Z1’s behavior in

both the time and frequency domains

with each of its six reconstruction

filters. The Sharp filter’s impulse

response was a conventional time-

symmetrical linear-phase type (not

shown), while the Short Delay Sharp

filter’s impulse response (fig.1) was

minimum-phase, with all the ring-

ing following the single high sample.

The Short Delay Slow filter’s impulse

response (fig.2) was also minimum-

phase, but, as its name implies, very

short. The impulse response of the

Low Dispersion Short Delay filter was

a hybrid type identical to that of the

Pro-Ject Pre Box S2 Digital’s Hybrid

filter^2 (not shown), while that of the

Standard mode shows the cover art and song info. Other

modes are Spectrum Analyzer (octave bands plus a couple

extra) and Analog Level Meter. The Library screen can be

accessed when a song is playing by swiping down and exited

by swiping up. Songs can be bookmarked or added to a

playlist.

Inside the box

Following the DMP-Z1’s premiere at the Hong Kong

Advanced Audiovisual Exhibition in the summer of 2018,

Rafe Arnott previewed it on our InnerFidelity website.^2

According to Rafe, the DMP-Z1 uses a pair of Asahi Kasei

Microdevices AK4497EQ DAC chips, a 32-bit part operat-

ing with PCM data at sample rates up to 768kHz, and DSD

data sampled at up to 22.4MHz. The AK4497EQ features

what AKM calls Velvet Sound technology, which appears to

be high-current capability, and also offers six choices for the

reconstruction filter, these operating with 32-bit precision.

Sony labels these filters Sharp, Slow, Short Delay Sharp,

Short Delay Slow, Super Slow, and Low Dispersion Short

Delay. A filter is selected by pressing the toolbox icon in the

percentage of battery charge is shown at the top right of the
touchscreen.) The player’s 256GB of internal storage can
be supplemented with two microSD cards, their mounting
slots concealed under a hinged panel on the player’s left
side. When you connect the DMP-Z1 to a host computer
with USB, the player asks if you want to turn on USB Mass
Storage. Touching “OK” mounts the internal storage drive
on your computer’s screen. To copy music files to the DMP-
Z1, Sony recommends their Music Center for PC app, or
drag’n’dropping content with Windows Explorer. Mac users
can simply copy files using the Finder. When you turn off
USB Mass Storage, the message “Creating Database” ap-
pears on the Sony’s screen, followed by the player’s Library
screen.

Playing music
Other than the four physical buttons, everything is con-
trolled with the DMP-Z1’s touchscreen. The Library screen
shows what music is stored on the player; the library can be
sorted by “All Songs,” “Album,” “Artist,” “Genre,” “Release
Year,” “Composer,” “Playlists,” and “Hi-Res.” This screen
also allows the user to select the USB DAC and Bluetooth
Receiver functions. When a song is playing, the screen in

MEASUREMENTS

Fig.3 Sony DMP-Z1, Slow filter, impulse response

(one sample at 0dBFS, 44.1kHz sampling, 4ms time

window).

Fig.1 Sony DMP-Z1, Short Delay Sharp filter,

impulse response (one sample at 0dBFS, 44.1kHz

sampling, 4ms time window).

Fig.4 Sony DMP-Z1, Sharp filter, wideband spec-

trum of white noise at –4dBFS (left channel red,

right magenta) and 19.1kHz tone at 0dBFS (left

blue, right cyan), with data sampled at 44.1kHz

(20dB/vertical div.).

Fig.2 Sony DMP-Z1, Short Delay Slow filter, impulse

response (one sample at 0dBFS, 44.1kHz sampling,

4ms time window).

1 See http://tinyurl.com/4ffpve4.

2 See fig.6 at https://tinyurl.com/y4ts9kf8.

2 See innerfidelity.com/content/sony-dmp-z1-8000-usd-digital-music-player-

unveiled.

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