Okto Research dac8 Stereo User manual

dac8 Stereo
Highest performance, streaming-enabled stereo D/A converter
Owner’s Manual

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Contents
Specifications ............................................................................................................................................... 3
Mechanical drawings ................................................................................................................................. 5
Back panel overview .................................................................................................................................. 6
Package contents ....................................................................................................................................... 6
Setting up ..................................................................................................................................................... 7
USB ............................................................................................................................................................. 7
Analog Connections .................................................................................................................................. 8
Main outputs ........................................................................................................................................... 8
Headphone output ................................................................................................................................ 8
Controls ......................................................................................................................................................... 9
Rotary control functionality ........................................................................................................... 9
Remote control functionality ......................................................................................................... 9
User interface and menu system .......................................................................................................... 10
Main screen – left display ............................................................................................................ 10
Main screen – right display ......................................................................................................... 10
Main menu........................................................................................................................................ 11
Volume submenu ........................................................................................................................... 11
Inputs submenu .............................................................................................................................. 12
Outputs submenu .......................................................................................................................... 12
System submenu ............................................................................................................................ 13
Displays submenu .......................................................................................................................... 13
Filters submenu .............................................................................................................................. 14
Status submenu .............................................................................................................................. 15
Using dac8 Stereo streaming capabilities .......................................................................................... 16
Warranty ..................................................................................................................................................... 18
Manual revisions ....................................................................................................................................... 18

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Specifications
Digital connectivity
 Inputs
o USB (asynchronous, UAC2.0 compliant), up to 384 kHz / 32-bit PCM, DSD256
or DoP128
o 2x Optical (Toslink)
o 2x Coaxial (SPDIF)
o AES/EBU (SPDIF voltage level compatible)
o Ethernet (through Raspberry Pi)
o Wi-Fi (through Raspberry Pi)
Analog connectivity
 Main outputs (back side)
o 2x XLR balanced, 2 connectors per channel
o 4.1V RMS full-scale
o output impedance: 50 Ohms
 Headphone output (front side)
o 6.3 mm (1/4”) TRS connector
o Output level: 4.1 V RMS full-scale
o 120 mA linear output current
o Output impedance <100 mOhm
Analog performance
 0.00003% / -130dB full-scale THD (Total Harmonic Distortion) or better
 0.0001% / 120dB full-scale SINAD or better
 131dB dynamic range
 0.00022 % / -113 dB THD+N @ 100 mW into 32 Ohms headphone output
Additional features
 Designed to directly interface to amplifiers
 Per-channel volume
 Choice between 7 PCM reconstruction FIR filters

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 Configurable auto on / auto off
 Configurable display timer for auto dim/off
 Remote control learning
 Trigger output
o 5 V voltage level
o short-circuit proof with 15 mA maximum current
o pulse or continuous
 Full control with either rotary or remote control
Dimensions
 446 mm x 183 mm x 50 mm
 Weight: 4.5 kg (10 lbs)
Power
 Mains voltage: 120 V AC or 230 V AC (depending on the country of order)
 Power rating: 15 W

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Mechanical drawings

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Back panel overview
Package contents
 dac8 Stereo (silver or black depending on your choice, 120 V or 230 V version
depending on the country of order)
Additionally, for the streaming version:
 Wi-Fi USB adapter with antenna
 USB interconnect
 blank 16 GB microSDHC memory card (inserted in the Raspberry Pi’s slot)
Optional accessories:
 Apple Remote (optional accessory)

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Setting up
USB
On Mac OS and Linux, no driver is needed thanks to the USB Audio Class 2.0 standard used
by the unit, and the dac8 Stereo will be recognized as an 8-channel playback device and an
8-channel recording device. The only action required by the user is to select the dac8 Stereo
in your operating system’s audio control panel.
This also applies to Windows 10 and newer, however, it is strongly recommended to use
ASIO to bypass the Windows sound mixer and allow for an exclusive access to the device
and a bit-perfect data transport.
To enable ASIO playback, please download and install the driver we provide.
Warning: The USB input of the dac8 Stereo may not work correctly (or at all) when
connected to a USB hub. It will also not work if connected to a USB 1.0 port. Be sure to use
a native USB 2.0, USB 3.0 or USB 3.1 port of your computer.

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Analog Connections
Main outputs
The main analog outputs provide an extremely accurate analog representation of the digital
signal received by the dac8 Stereo’s selected input.
The full-scale voltage level is 4.1 V RMS and the output impedance is 50 Ohm differentially.
The outputs are protected against long-term short circuit.
The volume control is always applied to the analog outputs. To bypass it, simply set it to
0 dB. Additionally, per-channel volume relative to the master volume can be applied if a
non-zero value is selected in the Volume menu.
Warning: we discourage from using balanced-to-unbalanced cables and converters. Doing
so will result in a vastly decreased analog performance and may be also cause of ground-
loop induced hum issues. Unbalanced signal paths (e.g. widespread RCA) are unsuitable for
device-to-device connections if high signal performance is desired, since they do not offer
a separate path for equalizing ground loop currents that will naturally occur in a real-world
environment. Additionally, XLR to RCA cables or converters commonly have XLR pin 3
shorted to ground, which will overload the dac8 PRO’s output stage and may even be cause
to damage after long-term use with high signal levels. In case you need to interface the
dac8 PRO to an amplifier with single-ended inputs only, please use cables without the short,
like “Benchmark XLRF to RCA adapter cable for analog audio – pin 3 floating”.
Headphone output
The headphone analog output, available on the front panel via a 6.3 mm (1/4”) TRS
connector, provides 4.1 V RMS full-scale voltage level, up to 120 mA linear current and less
than 100 mOhm output impedance. It is suited for majority of headphones and earphones,
ranging from 16 Ohm IEMs to a large 600 Ohm headphones with open construction.

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Short press: turn on, mute
Long press: turn off
(or three subsequent presses in case of some
remotes that don’t use the NEC protocol)
Enter menu, exit menu
Enter menu, select, confirm
Controls
dac8 Stereo can be fully controlled with either a rotary control including a push-on switch
or an IR remote in an intuitive way. Additionally, any IR remote can be used thanks to the
learning function. If you ordered an Apple Remote together with your dac8 Stereo, it will
come paired with the unit.
Rotary control functionality
Device state
Off Main screen Menu Menu,
selected
Input
Left/right
turn
- Volume
control
Navigation Modify
Push Turn on Enter menu Select Confirm
Long push Turn on Turn off Back Confirm
Remote control functionality
Volume- / Menu down
Volume+ / Menu up
Input change / Menu back

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dB
max
User interface and menu system
Main screen – left display
 Play / pause icon: indicates incoming data
 Input mode indicator: shows selected input mode
 Audio data information: shows sampling frequency, bit depth and data format (if
applicable to the selected input mode and incoming data type)
Main screen – right display
 Volume: current master volume in dB relative to the nominal full-scale output
 Mute icon: appears if mute is enabled using remote control or in the menu system
 Min / max indicator: only appears if the volume reaches upper limit (set in the Menu
> Volume > Lim) or minimum value (-99 dB)
USB
96kHz 24bit PCM

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Main menu
The main menu appears on the left display when the knob is pressed or a Menu or Enter
button is pressed on the remote control.
Volume submenu
 Mute: mutes all the analog outputs (default: off)
 Limit: sets the maximum allowed volume
o 0 to -50 dB (default: 0 dB)
 CH1, CH2 volume: an additional, per-channel volume relative to the master volume
Mute
USB sync off
Limit 0 dB
Left attn. 0 dB
Right attn. 0 dB
CH8 volume
0 dB
Volume
Inputs
Outputs
System
Displays
Filters
Status

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Inputs submenu
 Active: shows active (selected) input
 Use USB1 / USB2 / Coax1 / Coax2 / Opt1 / Opt2 / AES/EBU: Allow a respective
input to be selected
 Names: changes displayed name for the two USB inputs in respect to presence of a
streaming functionality
o USB / Stream
o USB1 / USB2
Outputs submenu
 L-ch source: selects signal source for the left output
o Left (default)
o Right
 R-ch source: selects signal source for the right output
Active USB
Use USB
Use Stream
Use Coax1
Use Coax2
Use Opt1
Use Opt2
Use AES/EBU
Names USB/Stream
L-
ch source Left
R-ch source Right

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o Left
o Right (default
System submenu
 Trigger: sets trigger output as continuous or 10 ms pulse on turn on and off
o cont. (default)
o pulse
 Auto ON: turn on the unit on incoming signal
 Auto OFF: turn off the unit after certain period with no signal present
o never
o 10 min
o 30 min
o 2 hrs (default)
 Learn remote: learn commands from any IR remote
 Load defaults: load factory defaults
Displays submenu
 Brightness: sets display brightness in 6 steps (default: 6)
 Timer: sets a timer to dim or turn off the displays
Auto ON
Auto OFF 2hrs
Trigger cont.
Learn remote
Load defaults
Brightness 6
Timer off
After timer dim
Menu return 60s

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o off (default)
o 10 s
o 60 s
o 5 min
 After timer: sets display action after the selected timer value expires
o off
o dim (default)
 Menu return: sets the time for an automatic return from the menu to the main screen
o off (default)
o 10 s
o 60 s
o 5 min
Filters submenu
 FIR filter
o FRLP (fast roll-off, linear phase)
o SRLP (slow roll-off, linear phase
o FRMP (fast roll-off, minimum phase) (default)
o SRMP (slow roll-off, minimum phase)
o AFRLP (apodizing, fast roll-off, linear phase)
o HFRMP (hybrid, fast roll-off, minimum phase)
o BW (brickwall filter)
 DSD filter – sets the cut-off frequency of the low-pass filter for DSD playback
o auto (default)
o 50 kHz
o 60 kHz
o 70 kHz
PCM filter FRMP
DSD filter auto

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Status submenu
 Serial number – shows the serial number that is burned in the OTP (one-time-
programmable) memory. The reading will not be affected by firmware updates.
 FW version – shows the current version of the device firmware
 Temperature – reading of the temperature at the DAC8 module
 Uptime – shows the elapsed time since the unit was powered on
Serial number 8
FW version 1
Temperature 35°C
Uptime 1:22:33

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Using dac8 Stereo streaming capabilities
If ordered with the streaming option, the dac8 Stereo will come with a built-in Raspberry Pi
and allows user to install a streaming distribution of their choice. Please follow these steps
to ensure a flawless installation.
1) Insert the memory card into your computer.
2) Pick a streaming distribution of your choice, download an image file and flash it
onto an SD card with a recommended tool. Usually, it is Etcher.

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3) Make sure your dac8 Stereo is unplugged from mains and remove the top cover.
4) Put the MicroSD card into the Raspberry Pi slot
5) Mount the top cover back in place
6) Plug-in the Wi-Fi adapter and USB interconnect and plug the unit back into mains
Even if you don’t intend to use Wi-Fi, keep the adapter in place. Disconnecting it would
make the Raspberry use its on-board Wi-Fi radio, which might create audible interference.

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Warranty
The dac8 Stereo is designed for a maximum reliability and each unit is tested extensively
before it is shipped. However, if a spontaneous malfunction occurs, the product is covered
with a 2-year warranty. Please be aware that any damage caused by abusive operation is
not covered.
To ensure your satisfaction, we also offer a 30-day return policy. In case of a return, the
customer pays the cost of the shipping back to us and the refunded amount does not
include the cost of the previous shipping from us to the customer. The returned product
and accessories must be complete, clean and free of scratches and other damage.
When receiving the product, customer is required to carefully check the package for
damage and if some is present, require the delivery person to document the damage and
write a report. This report, together with photographs, then needs to be e-mailed to us as
soon as possible. If these steps are not taken, the transportation damage will not be covered
by the warranty. The address for returns is as follows:
Okto Research s.r.o.
Jana Masaryka 257/26
12000 Prague
Czech Republic
[email protected]
www.oktoresearch.com
Manual revisions
Rev. 1.1
Small changes
, extended XLR
-
to
-
RCA disclaimer,
mailing
address update
Rev. 1.0
Initial
release
ASIO is a trademark of Steinberg Media Technologies GmbH.