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Please note that this is a work in progress.
A couple of years ago, I started accumulating parts for a DAC build that would allow me to play back my collection of SACD rips.
I had been using a Logitech Touch with EDO app into a CEntrance DACmini.
A couple of things pushed me into finally starting on the project, I trialed Roon software for a month and I had a chance to use a Raspberry Pi with Kali reclocker board and the Allo Piano DAC board.
Those items changed my perception of what is now available for digital playback and how good it all can sound.
I subscribed to Roon and ordered an Odroid C2 in which I installed DietPi and Roon Bridge. I finally put all the parts together to build the DAC
This is a proof of concept build. There will be many changes to the layout as times passes.
I started with a chassis I had on hand. It had many holes already drilled and I have drilled many more trying different layouts.
As DAC chips seem to change at least once a year, I did not want a full DAC on one board. I chose to break out the sections according to their use.
I decided to use separate transformers for the USB and DAC boards. I went with R cores, I used a 3 pole snubber after the transformer to remove any ringing in the transformer secondaries along with soft recovery diodes. I also used Jensen four pole capacitors for additional isolation. they are part of the CRC network prior to going int the Salas Reflektor Shunt regulators.
The USB board is the I2SoverUSB by JL Sounds. Some of the features of this board are:
"I2SoverUSB uses reclock to reduce jitter significantly. I2S, S/PDIF outputs, oscillators and reclock are galvanically isolated from XMOS processor and USB ground. The galvanic isolation eliminates common noise originated by the computer. There is an galvanically isolated external master clock input. The board is equipped with NDK NZ2520SD low jitter oscillators 45.158MHz and 49.152MHz. LP5900 ultra-low noise linear voltage regulators are used"
The DAC board plugs directly into the USB board.
I decided on the JL Sounds AK4490 as it offers Direct DSD (no conversion to PCM) and the ability to choose from 5 different filters.
"Native DSD Support
Supports 2.8MHz (64fs), 5.6MHz (126fs) and 11.2MHz (256fs) DSD
According to AKM, the volume control module and the delta-sigma modulator can be bypassed for DSD resulting in “direct” DSD rendering. The AK4490 contains an integrated low-pass filter specifically for DSD data."
By moving a couple of jumpers around on the boards, I am able to power each board separately from the Salas regulators.
For the proof of concept build I decided to just use the analog output from JL Sounds. As the project moves along, I hope to try out a tube analog section.
The analog section uses a toroidal transformer. I used a 3 pole snubber and Jensen caps again for smoothing and as part of a CRC before the regulators
[IMG]http://www.htguide.com/forum/attachm...1&d=1502643373[/IMG]
The regulators are the Simple Salas Low Voltage (Back in Black) With the stock op-amps the regulators were set for +- 15 v.
Changing the op amps to the Sparkos Labs discrete op amps I am now running them at 16 volts
Overall. I am very happy with the way the build is turning out. Using Roon I am able to upsample all my files to DSD256 and stream all day with no dropouts or glitches.
The next step my be to relocate the Odroid into the same case as the DAC and run I2S direct to it and eliminate the USB step.
Thanks for taking the time to look over my little project.
A couple of years ago, I started accumulating parts for a DAC build that would allow me to play back my collection of SACD rips.
I had been using a Logitech Touch with EDO app into a CEntrance DACmini.
A couple of things pushed me into finally starting on the project, I trialed Roon software for a month and I had a chance to use a Raspberry Pi with Kali reclocker board and the Allo Piano DAC board.
Those items changed my perception of what is now available for digital playback and how good it all can sound.
I subscribed to Roon and ordered an Odroid C2 in which I installed DietPi and Roon Bridge. I finally put all the parts together to build the DAC
This is a proof of concept build. There will be many changes to the layout as times passes.
I started with a chassis I had on hand. It had many holes already drilled and I have drilled many more trying different layouts.
As DAC chips seem to change at least once a year, I did not want a full DAC on one board. I chose to break out the sections according to their use.
I decided to use separate transformers for the USB and DAC boards. I went with R cores, I used a 3 pole snubber after the transformer to remove any ringing in the transformer secondaries along with soft recovery diodes. I also used Jensen four pole capacitors for additional isolation. they are part of the CRC network prior to going int the Salas Reflektor Shunt regulators.
The USB board is the I2SoverUSB by JL Sounds. Some of the features of this board are:
"I2SoverUSB uses reclock to reduce jitter significantly. I2S, S/PDIF outputs, oscillators and reclock are galvanically isolated from XMOS processor and USB ground. The galvanic isolation eliminates common noise originated by the computer. There is an galvanically isolated external master clock input. The board is equipped with NDK NZ2520SD low jitter oscillators 45.158MHz and 49.152MHz. LP5900 ultra-low noise linear voltage regulators are used"
The DAC board plugs directly into the USB board.
I decided on the JL Sounds AK4490 as it offers Direct DSD (no conversion to PCM) and the ability to choose from 5 different filters.
"Native DSD Support
Supports 2.8MHz (64fs), 5.6MHz (126fs) and 11.2MHz (256fs) DSD
According to AKM, the volume control module and the delta-sigma modulator can be bypassed for DSD resulting in “direct” DSD rendering. The AK4490 contains an integrated low-pass filter specifically for DSD data."
By moving a couple of jumpers around on the boards, I am able to power each board separately from the Salas regulators.
For the proof of concept build I decided to just use the analog output from JL Sounds. As the project moves along, I hope to try out a tube analog section.
The analog section uses a toroidal transformer. I used a 3 pole snubber and Jensen caps again for smoothing and as part of a CRC before the regulators
[IMG]http://www.htguide.com/forum/attachm...1&d=1502643373[/IMG]
The regulators are the Simple Salas Low Voltage (Back in Black) With the stock op-amps the regulators were set for +- 15 v.
Changing the op amps to the Sparkos Labs discrete op amps I am now running them at 16 volts
Overall. I am very happy with the way the build is turning out. Using Roon I am able to upsample all my files to DSD256 and stream all day with no dropouts or glitches.
The next step my be to relocate the Odroid into the same case as the DAC and run I2S direct to it and eliminate the USB step.
Thanks for taking the time to look over my little project.
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