Soekris dac1321 User manual

www.soekris.dk 1 Dec 2017
dac1321 Users Manual
Discrete R-2R DAC

Soekris Engineering ApS dac1321 Users Manual
www.soekris.dk 2 Dec 2017
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Soekris Engineering ApS dac1321 Users Manual
www.soekris.dk 3 Dec 2017
Introduction
The Soekris dac1321 is a low cost Audiophile discrete R-2R DAC only, with USB and SPDIF
inputs and line level outputs on rear mounted RCA Phono connectors. The dac1321 is not just any
regular DAC, the sound quality is the absolute best available, thanks to the ultra high end design
with a discrete R-2R sign magnitude DAC using a about 200 small and very precise resistors,
output amplifiers with zero negative feedback, powered by either USB power or an external power
supply, with two discrete linear low noise and low impedance power regulators and one low noise
regulators for the digital parts.
The dac1321 R-2R DAC circuit is fully isolated from the noisy computer USB interface and the
SPDIF inputs are also all transformer isolated. It supports input signals on the USB interface up to
24 bit / 384 Khz PCM audio, and up to DoP-128 (x2) and DSD-256 (x4) audio, or up to 24 bit / 192
Khz PCM audio on the various SPDIF interfaces. It has a fully digital volume control and four sets
of digital anti-aliasing filters to fit any taste. The dac1321 is designed and built in Denmark, using
advanced surface mount technology and parts from only the highest quality suppliers, with a full
aluminum casing.
Quick Start
Plug in the supplied USB Cable to the dac1321 and connect it to your computer, connect your
amplifier to the RCA Line Out sockets, set the rear right switch to “USB1”, select “soekris
dac1xxx” as output in your computer settings and start playing music. The default power up
settings for volume and anti-aliasing filters are stored in flash memory and can be changed, see
front view description for details.

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Specifications
THD @ -1 dB
<0.012%
THD @ -60 dB
<0.04%
Clock Jitter RMS
0.8 pS typical
Discrete Resistor Network
25 bit, 0.02% - 0.05% Resistors
S/N 20 Khz Bandwidth
>120 dB unweighted
Frequency Range @ 44.1 Khz
20hz - 20Khz +0.1 -1.0 dB
Frequency Range @ 384 Khz
20hz - 80Khz +0.1 -1.0 dB
USB Input
Type B, Isolated, Full / High Speed
USB Input Mode Selectable
Audio Class 1.0 or Audio Class 2.0
USB Input PCM
Up to 24 Bit / 384 Ksps
USB Input DSD
Up to DoP-128 and DSD-256
SPDIF Inputs
RCA / Toslink
SPDIF Inputs PCM
Up to 24 bit / 192 Khz
Digital volume control
-80 dB to +10 dB
Output Line
RCA, 2.0V RMS, Zout 10 ohm
Power Consumption
From USB or 5V DC Plug, max 3W
Size
140 x 185 x 30 mm
Weight
0.4 Kg
Warranty
3 Years

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dac1321 front view
The LED’s on the front indicates input sample rate, input source, anti-aliasing filters selected and a
clip indicator.
When input is Linear PCM audio
When input is DSD or DoP audio
PCM 44/48 Khz
“X1” LED on
DoP/DSD-64
“DSD” on
PCM 88/96 Khz
“X2” LED on
DoP/DSD-128
“DSD” and “X2” on
PCM 176/192 Khz
“X4” LED on
DoP/DSD-256
“DSD” and “X4” on
PCM 352/384 Khz
“X8” LED on
“INPUT” button: Select between the possible input source and an automatic mode, which is the
default at power up.
“FILTER” button: Select between the different anti-aliasing filters. Hold for minimum 4 seconds
to store the current volume level and anti-aliasing filter selection.
“FILTER” LED color shows the current anti-aliasing filter selected
Red
Linear Phase filter, also called brickwall filter
Orange
Mix between Linear and Minimum Phase filter
Green
Minimum Phase filter, also called butterworth filter
Off
Soft Minimum Phase filter, a soft butterworth filter
Volume LED:The volume LED brightness indicates current volume, from -80 dB to +10 dB. The
volume knob is using a digital encoder to set the volume level digitally from -80 dB to +10 dB in
precise 1 dB steps. If you connect the Line Out to a system with a volume knob you might want to
set the dac1321 Line Out volume startup level to a fixed 0 dB, you can do that by turning the
volume up to -4 or higher, easiest is just to turn it full up (without music playing), then store the
startup setting by pressing and holding the “FILTER” button for 4 seconds. The volume control is
then inactive, it can be made active again by holding the “FILTER” button for 4 seconds again.
“CLIP”The Volume LED will blink RED when the DAC output signal is clipping. You should
not turn the volume knob higher than to where the red “CLIP” LED will not blink.

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dac1321 rear view
Analog Out: The dac1321 have single ended line out using RCA sockets, the red one marked “R”
is for the right channel, the white one marked “L” is for the left channel.
Digital In: The dac1321 have a total of 3 digital inputs.
“TOS”:SPDIF Optical Toslink.
“RCA”:SPDIF 75 ohms Coax, transformer isolated.
“USB”: USB type B socket: For connection to the USB interface on your computer or other audio
source device. You need to use a high quality USB cable, like the USB cable included with the
dac1321. The switch next to the USB socket is used to select between USB Audio Mode 1, which
can be used without drivers on Windows operating systems, and USB Audio Mode 2, which
require drivers for Windows operating systems.
Windows Drivers: Drivers for using USB Audio Mode 2 on Windows operating systems are
available for downloading on http://www.soekris.dk/download.html. Please note that most newer
versions of Apple OS X or Linux don’t require drivers but will support USB Audio Mode 2
directly, see manual for your operating systems as needed.
Power Socket: The dac1321 support power from the USB interface, or you can use an external 5V
1A DC power supply with a 5.5mm outside, 2.1mm inside female power plug with plus at center
pin, like the included power supply.
Power Switch: Used to turn the dac1321 power on and off.

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Conformity Declarations
This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to Part 15 of the FCC rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and used in
accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that the interference will not occur in a particular installation. If this
equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that of the receiver.
- Consult the dealer or an experienced radio/TV technician for help.
In order to maintain compliance with FCC regulations shielded cables must be used with this
equipment. Operation with non-approved equipment or unshielded cables is likely to result in
interference to radio & television reception.
Application for Council Directives 2011/65/EU, 2014/30/EU
Conformity declared for EN55022 Class B, EN55024
This marking indicates that this product should not be disposed with other household
waste throughout the EU. To prevent possible harm to the environment or human health
from uncontrolled waste disposal and to conserve material resources, this product
should be recycled responsibly. To dispose of your product, please use your local return
and collection systems.
Contact Information
Soekris Engineering ApS
Servicevej 6
DK-4220 Korsør
Denmark
http://www.soekris.dk
[email protected]