Okto Research DAC8 PRO User manual

DAC8 PRO
The nicest 8-channel D/A converter
Owner’s manual

2 | DAC8 PRO Owner’s Manual
Contents
Technical speci ications ............................................................................................................................. 3
Mechanical drawings ................................................................................................................................. 5
Back panel overview .................................................................................................................................. 6
Package contents ....................................................................................................................................... 6
Digital connections ..................................................................................................................................... 7
USB ............................................................................................................................................................. 7
Host drivers ....................................................................................................................................... 7
AES/EBU .................................................................................................................................................... 9
Analog Connections ................................................................................................................................ 10
Main outputs ......................................................................................................................................... 10
Headphone output .............................................................................................................................. 10
Input modes ................................................................................................................................................ 11
Pure USB .................................................................................................................................................. 11
USB / AES ................................................................................................................................................ 11
Pure AES .................................................................................................................................................. 11
Controls ....................................................................................................................................................... 12
Rotary control unctionality ......................................................................................................... 12
Remote control unctionality ....................................................................................................... 12
User inter ace and menu system .......................................................................................................... 13
Main screen – le t display ............................................................................................................ 13
Main screen – right display ......................................................................................................... 13
Main menu....................................................................................................................................... 14
Volume submenu .......................................................................................................................... 14
Routing submenu .......................................................................................................................... 15
System submenu ............................................................................................................................ 15
Displays submenu .......................................................................................................................... 16
Filters submenu .............................................................................................................................. 16
Status submenu .............................................................................................................................. 17
Warranty ..................................................................................................................................................... 18
Manual revisions ....................................................................................................................................... 18

3 | DAC8 PRO Owner’s Manual
Technical speci ications
Digital connectivity
•USB
o8 output and 8 input channels
oasynchronous, UAC 2.0 compliant
oplayback data ormats
PCM, up to 192kHz / 32-bit
native DSD, 64x / 128x
DSD over PCM (DoP), 64x
orecording data ormat
PCM, up to 192kHz / 32-bit
•AES/EBU
o4 AES/EBU inputs (SPDIF compatible)
up to 192 kHz / 24-bit
resampling- ree (i.e. requiring a single signal source)
unique USB/AES input mode ensures a bit-per ect data low rom
AES/EBU to USB, allowing or a real-time signal processing or
simultaneous recording & playback with no resampling applied
o1 AES/EBU output
ixed to playback channels 1 and 2 (o USB or AES/EBU, depending on
the selected input)
Analog connectivity
•Main outputs (back side)
o8 x Neutrik gold-plated XLR connector
oOutput level: 4.1 V RMS di erential ull-scale
ooutput impedance: 200 Ohms
•Headphone output ( ront side)
o6.3 mm (1/4”) TRS connector
oOutput level: 4.1 V RMS ull-scale
o120 mA linear output current
oixed to output channels 1 and 2
ooutput impedance <100 mOhm

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Analog per ormance
•0.000032 % / -130 dB THD (Total Harmonic Distortion) ull-scale, 1kHz
•0.00011 % / -119 dB THD+N (Total Harmonic Distortion + Noise) or 119 dB SINAD
ull-scale, 1kHz
•125 dB dynamic range
•0.000224 % / -113 dB THD+N @ 100 mW into 32 Ohms headphone output
Menu unctions
•Individual volume or each o the 8 output channels (relative to the master volume)
•Routing matrix (any input channel to a speci ic output channel)
•Upper volume limit
•Remote control learning
•Choice between 7 PCM reconstruction FIR ilters
•Con igurable display timer to dim or turn o the displays
•Con igurable auto on / auto o with non-zero audio data detection
Other eatures
•Trigger output
o5 V voltage level
oshort-circuit proo with 15 mA maximum current
opulse or continuous
•Full control with either rotary or remote control
•Rack-mountable with optional 2U, 19” rack mounting brackets
Dimensions
•448 mm x 183 mm x 50 mm, excluding user-removable eet
•Weight: 4.5 kg (10 lbs)
Power
•Mains voltage: 120 V AC or 230 V AC (depending on the country o order)
•Power rating: 15 W

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Mechanical drawings

6 | DAC8 PRO Owner’s Manual
Back panel overview
Package contents
•DAC8 PRO (silver or black depending on your choice, 120 V or 230 V version
depending on the country o order)
•USB cable (black, 2 m)
•Apple Remote (optional)
•Rack mounting brackets (optional)

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Digital connections
USB
Host drivers
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 PRO 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 PRO
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 or an exclusive access to the device
and a bit-per ect data transport. Please contact us i you are interested in using the DAC8
PRO with older Windows operating systems.
To enable ASIO playback, please download the latest version o ASIO4ALL driver rom
asio4all.org and ollow the installation steps.
A ter the installation is complete, you will be able to see “ASIO4ALL v2” as an output device
option in any ASIO capable playback so tware. The ollowing picture displays the output
device setting in JRiver:

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Our recommendation: not all Windows applications are capable o ASIO output ( or
example a Spoti y desktop app or the Chrome browser). However, you are still able to
achieve an ASIO playback with “ASIO Bridge / Hi – Fi Cable” by VB-Audio, that is available
as a donationware on vb-audio.com/Cable/. A ter being installed, the ASIO Bridge will
appear as a new audio output audio device and needs to be selected as de ault:

9 | DAC8 PRO Owner’s Manual
The actual ASIO output o the ASIO Bridge needs to be selected in the application’s control
panel (that can be accessed a ter clicking the icon on Windows taskbar) by clicking on “ASIO
Device” text string:
Please consider donating to the creators o both ASIO4ALL and ASIO Bridge i you like their
work.
Warning: The USB input o the DAC8 PRO may not work correctly (or at all) when connected
to a USB hub. It will also not work i connected to a USB 1.0 port. Be sure to use a native
USB 2.0, USB 3.0 or USB 3.1 port o your computer.
AES/EBU
The DAC8 PRO o ers 4 AES/EBU inputs that are ree o resampling. That allows or a bit-
per ect playback by the DAC8 PRO as well as recording at the USB host side, but it also
requires the inputs to be mutually synchronized and carry signals with matching sampling
rates.
Additionally, i only one input is used, it needs to be the input 1. I 2 o them are used, they
need to be the inputs 1 and 2. There is no requirement or inputs 3 and 4.
The AES/EBU inputs will also accept a signal with the lower SPDIF voltage levels and while
the requirement or termination impedance is di erent or the two standards, the SPDIF
signal will generally be received correctly i the cables are not too long to cause signi icant
re lections resulting in data corruption.

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Analog Connections
Main outputs
The main analog outputs provide an extremely accurate analog representation o the digital
signal received by the DAC8 PRO’s selected input.
The ull-scale voltage level is 4.1 V RMS and the output impedance is 200 Ohm di erentially.
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 i a
non-zero value is selected in the Volume menu.
Warning: we discourage rom using balanced-to-unbalanced cables and converters. Doing
so will result in a vastly decreased analog per ormance and may be also cause o ground-
loop induced hum issues. Unbalanced signal paths (e.g. widespread RCA) are unsuitable or
device-to-device connections i high signal per ormance is desired, since they do not o er
a separate path or equalizing ground loop currents that will naturally occur in a real-world
environment.
Headphone output
The headphone analog output, available on the ront panel via a 6.3 mm (1/4”) TRS
connector, provides 4.1 V RMS ull-scale voltage level, up to 120 mA linear current and less
than 100 mOhm output impedance. It is suited or majority o headphones and earphones,
ranging rom 16 Ohm IEMs to a large 600 Ohm headphones with open construction.