Dec 2018 - preview
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Network Audio
DAC Dec 2018 - preview |
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INTRODUCTION
I can guarantee that DSC1 2.5 / 2.6 is the best digital source and the maximum sonic performance can only be achieved using the software HQPlayer desktop.
This software is available for Windows, Linux and macOS and it have many algorithm for noise filters which allow many sound variations.
The embedded version of HQPlayer is designed for building Linux-based music playback devices and digital audio processors.
HQPlayer embedded is a
daemon server running on a dedicated hardware so it is immune to any
interference allowing a perfect reproduction of any track at high bitrate
also during the PCM to DSD on-the-fly convertion.
About the DAC hardware I keep experimenting new solutions based on DSC1 with
Pavel Pogodin
and here the Pure DSD DAC with and without USB
input.
In the following photos the new DAC module with
Amanero Combo384 USB interface
(left) and with the
BeagleBone board (right).
The NAA protocol has been design by Jussi Laako of
Signalyst and this use normal full
TCP/IP stack plus XML with some crypto algorithms for authentication so it
is very simple if compared to professional standards which have as main
objective the synchronism of the clock of various slave devices.
The NAA run without problem on 100 Mbps LAN at DSD512 data rate.
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Here my implementation with volume control by CT2 DACT stepper attenuator with the Bent Audio remote control and the CT3 DACT as analog input selector.
Here the implementation of
Pavel Pogodin using RoonServer + HQPlayer
Embeded + new DSC2.
Here more info about this modules created by
Pavel Pogodin.
OUTPUT TRANSFORMERS
The output trasformers has been selected by
Pavel Pogodin
after many test and also I have compared these with other models with much
higher cost.
These have
a turn ratio of 2:1+1, made with a permalloy core with a thickness of 0.16mm and
an inductance about 340H.
The declared frequency response is 10Hz - 195 KHz
at -0.2dB for the yellow and 20Hz - 80 KHz at -0.2dB for the black type
I
still need to test the black type but
Pavel Pogodin told me that yellow has more "air" and black are
probably more balanced but it all depends very much on the record or even his
mood.
CHOICE OF HARDWARE
This new DAC by
Pavel Pogodin is compatible with BeagleBone
Black and Green but the last one have a better build and no extra hdmi.
On
this little board run a very little custom Linux near to a firmware able to work
simultaneously with RoonBridge
and the Network Audio Adapter for
HQPlayer.
The BeagleBone Green is based on the open-source hardware design with the Processor: AM335x 1GHz ARMŽ Cortex-A8, 512MB DDR3 RAM and 4GB 8-bit eMMC on-board flash storage.
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The normal power supply input for the BeagleBone is the micro USB but it is
possible to provide 5V to the main board from an expansion board.
By
supplying a 5V signal into the VDD_5V rail, the main board can be supplied. This
voltage must not exceed 5V.
You should not supply any voltage into any
other pin of the expansion connectors.
There are 2 more power supply necessary for the DAC module.
In order to have these 3 voltages, 5V 1A for the
BeagleBone Green, 5V for the DAC and 8V for the DAC
I have buy these 2 power supply module on
Alixpress.
The BeagleBone use the
TS65217 chip
power management and the DC supply must ramp up sufficiently rapidly (within 50
ms) to trigger power-up otherwise this chip enters some kind of lockup state and
cpu does not switch-on. In the order of
the Triple Independent
Linear Regulator ask for 3.3V
(Amanero if necessary), 5V and 8V. Add a good 9V 30VA and a 6.5 - 7V 30VA
transformer. The power supply transformer has been created on my
specification with an extreme low flux.
High Speed Low Noise Triple Independent Linear
Regulator Power Supply only 10-15$ and LT1083 adjustable power supply board only
5-15$ for the BeagleBone (to set at 5V).
In the LT1083 module I have replaced the 4700uF
with a 1000uF 16V, eliminated the yellow fuse and connected the heatsink to
ground.
The primary has been calculated
for 260V instead of 220V to keep the flux at 14000 gauss.
The company
used for this product is Italtras.
V primary
gauss
V primary
gauss
V primary
220
17000
1.18
259.6
14000
260V
V second.
A sec
VA
17000/14000
V second.
A second.
VA
V second.
A sec
VA
15
0.2
3
1.18
17.7
0.4
7.08
18
0.2
3.6
15
0.2
3
1.18
17.7
0.4
7.08
18
0.2
3.6
6.5
2
13
1.18
7.67
0.2
1.534
7.7
3
23.1
9
1
9
1.18
10.62
5
53.1
10.6
1
10.6
total
28
total
68.794
total
40.9
In my case there is an added seconady 18V-0-18V to power a BUF634 buffer to isolate the main output from the subwoofer of my Monitor 4.
OPERATING SYSTEM INSTALLATION
It is necessary install the BeagleBone firmware designed specifically for this board.
Installation
1. Uncompress with 7z the file Arch_Botic_DSC2.gz
2. Copy on a 16Gb micro SD using
the free windows software
Win32DiskImage.
5. Connect the USB to serial adapter to
BeagleBone module
Now you need to connect the PC to the BeagleBone board on console using an USB to serial adapter for 3.3V.
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Use only ground, tx and rx pin from USB to serial adapter.
6.The Putty is an open source software a serial / SSH client.
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THE HQPLAYER / HQPLAYERD CONFIGURATION
To configure the HQPlayerd open the website on port 8088.
I suggest to set the Output mode to SDM to convert output in DSD, the modulator to ASDM7 or ADSM5 (if no cpu resource available with 7) and Bitrate at 11289600 Hz or 12288000Hz for a DSD256 setup.
BUF634 Buffer
I am using a BUF634 buffer to isolate the main output from the subwoofer of my Monitor 4.
