back to
www.audiodesignguide.com

To get more information contact me at: webmaster@audiodesignguide.com

 

Pure DSD - The USB DAC converter without a DAC chip
Jan 2016 -

INTRODUCTION

Update Nov. 2016: After many test I was not able to completely eliminate  the digital noise on output also using separated power supply for the Amanero and also using isolator on I2S bus so I don't suggest this project.

T
he DSD signal can be directly used to reconstruct the original analog signal with a simple RC filter.
This method allow to create a very simple DAC without a DAC chip with sonic performance near to normal DACs.
At this time there is only a commercial product using this method to convert digital signal to analog output by LampizatOr (see review).
The output wave have a DC component of 1.65V present only during DSD playing so with a normal firmware if you change track or click pause a high bump will be reproduced on loudpseakers.
I have an active collaboration with Amanero srl so I have request this new firmware that keep an empty output signal any time there is not DSD signal to reproduce.
Using this software there is a bump only at the switch-on and switch-off but you can add a relay to eliminate this problem.
This DAC work only with DSD but you can play any PCM tracks converting these in DSD with some setting on your JRiver or Foobar2000 player while this playing.
There is a big benefit to convert tracks in DSD also using a normal DAC DSD converters (Korg document , Archimago's Musings ).
I suggest to use PC with Intel® Core™i3 min and a RAM 4Gb but also on some Android device the convertion should work with Onkyo HF Player .

USB to DSD module + Firmware DSD only + passive filter

It is very simple the connection with Amaero module but you can see the complete datasheet whre are indicated the pins (datasheet).

To eliminate the noise coming from the PC power supply cut the wire on pcb near the USB connector and use an external 6-5Vdc.
Also 3 x 1.5V batteries could be used.
I have add a 220uF 6.3V Sanyo OS-CON capacitor on 3.3V output pins.

 

 

Firmware DSD only

I have an active collaboration with Amanero srl so I have request this new firmware to eliminate the bump during the switch tracks and stop.

1) Download the ConfigTool and unzip in a folder, for example on Desktop.

2) Erase the flash following these steps




3) When you replug the erased device, Windows can ask about a driver so acept this. 

4) Be sure to be connected to internet.

5) Run ConfigOEM118.exe and after the choice of CPLD and CPU firmware press the relative Flash button. 

6) When done close ConfigTool.exe and Unplug the USB Cable.

7) Replug the USB cable and if it's all ok the audio driver needs to detect the device.

 

JRiver configuration

JRiver is a Media Center software able to play any PCM and DSD format including SACD iso images.

 

Foobar2000 configuration

The Foobar2000 is an advanced freeware audio player for the Windows platform.
It is necessary download some components to add to the normal installation, these are auto install parts or .dll to insert in the components directory.

 

Measurement

 

Simulation