DISCRETE R-2R DAC for raspberry pi

[yannig]

I would prefer to have a digital interpolator.
But it could be done with a separate board...
With the DAC board(s) stacked on top.

[bigbulb]

@bigbulb, what are your plans for this unique DAC?

It does not seem like the design lends itself to mass production unless you are setup to do something like Soekris did but I'm sure, myself included, there are audio enthusiasts that would want to buy one of these from you.

Let us know :-)

Hi Tim, 


My previous AD1865 DAC hat was hand made.  To Date, 80++ units had been sold .

For this discrete R2R DAC, since the resistors need to hand - picked , I'm thinking of building a small match at one time. 
I already assembled 10 units and 7 had been sold last week. Start building second batch now.
Need to find a good way to build it fast and reduce building cost.

I'm currently designing and building an adapter board  as an add-on board with linear power supply on it, and also a socket to accept an Amanero USB module, so that I can use it as a stand alone USB DAC. 
Will post here once I finish and test the USB adapter board .

[bigbulb]

@bigbulb, what are your plans for this unique DAC?

It does not seem like the design lends itself to mass production unless you are setup to do something like Soekris did but I'm sure, myself included, there are audio enthusiasts that would want to buy one of these from you.

Let us know :-)

Is the DAC delivered "soldered" ready?
What should it cost?
How about moode?

Maybe you can make a bulk order to adjust the price.

is just an idea of mine and doesn't have to agree with others ..

Ciao Zeferino

Hi Ciao, 

The DAC need to be fully assembled and tested before I send it out. 
I need to adjust the MSB trim as well. 
Bulk order seem not really work at the moment, I need to find a way to lowered the cost and also assembling time.

[hifinet]

After nearly forty years of SD DACs, it's over. While listening to my latest SMSL Sanskrit 10th Mk II, it hit me. Digital horns? WTH? All these years and still digital horns. Decided to go the NOS DAC route. Finally, natural sounding horns, and more. I listen exclusively to acoustic music, classical in all forms. After listening to NOS DACs, the SMSL was distorting the acoustics. Sound was like 2D TV versus a 3D reality. I now own this wonderful DAC. In short, it is a stunning achievement in sound quality.

[Tim Curtis]

Nice :-) Its included in the device list as "EWCG Discrete R2R DAC" for upcoming moOde 7. @bigbulb generously sent me a sample unit but I have not had time to test it yet due to the heavy amount of work for 7...

[hifinet]

I started with his AD1865, since it is a well known and respected DAC chip. This discrete DAC is decidedly better, with lower noise and distortion, and rock solid precise imaging and a bit wider soundstage. As recommended, I have it powered completely from the RPi. It has a built in I2S isolator. Sorting and soldering 96 itty bitty SMD resistor critters and programming the FPGA. Dang!

[Gromit]

Very interesting project, well done!

As moode 7 is now officially released, can somebody confirm that the DAC works with this moode 7 release?

[bigbulb]

Very interesting project, well done!

As moode 7 is now officially released, can somebody confirm that the DAC works with this moode 7 release?

Hi Gromit, 

The latest Moode 7 actually included a new driver for this R2R DAC design. 
The Driver is "EWCG Discrete R2R DAC"

[laurelsudeep]

I am unable to detect this DAC on my Spotify connect. I am seeing this "Hardware volume controller not detected" in the ALSA volume
Unable to get software control.

No issues on other DACs like Allo.


M O O D E   S T A R T U P   L O G

Code:

20220130 001453 worker: -- Start
20220130 001453 worker: Successfully daemonized
20220130 001454 worker: Integrity check (passed)
20220130 001454 worker: File check (OK)
20220130 001455 worker: Session vacuumed
20220130 001455 worker: Session loaded
20220130 001455 worker: Debug logging (OFF)
20220130 001455 worker: -- Audio debug
20220130 001455 worker: ALSA cards: (0:sndrpirpidac | 1:empty | 2:empty | 3:empty
20220130 001455 worker: MPD config: (0:EWCG Discrete R2R DAC | mixer:(none) | card:0)
20220130 001455 worker: ALSA mixer actual (none)
20220130 001455 worker: ALSA volume (none)
20220130 001455 worker: -- System
20220130 001456 worker: Host     (moode)
20220130 001456 worker: moOde    (7.6.1 2021-12-17)
20220130 001456 worker: RaspiOS  (10.6)
20220130 001456 worker: Kernel   (5.4.77-v7l+ #1371)
20220130 001456 worker: Platform (Pi-4B 1.4 4GB)
20220130 001456 worker: ARM arch (armv7l, 32-bit kernel)
20220130 001456 worker: MPD ver  (0.23.4_p0x3)
20220130 001456 worker: CPU gov  (ondemand)
20220130 001456 worker: USB boot not available
20220130 001456 worker: File system not expanded yet
20220130 001456 worker: HDMI port on
20220130 001456 worker: -- Network
20220130 001456 worker: IP address check timeout (90 secs)
20220130 001456 worker: eth0 adapter exists
20220130 001456 worker: eth0 IP address check (No)
20220130 001456 worker: IP addr (192.168.1.81)
20220130 001456 worker: Netmask (255.255.255.0)
20220130 001456 worker: Gateway (192.168.1.254)
20220130 001456 worker: Pri DNS (192.168.1.254)
20220130 001456 worker: Domain  (None)
20220130 001456 worker: wlan0 adapter exists
20220130 001456 worker: wifi country (US)
20220130 001456 worker: wlan0 SSID is blank
20220130 001456 worker: eth0 addr exists, AP mode not started
20220130 001456 worker: wlan0 address not assigned
20220130 001457 worker: Pi integrated wlan0 power save disabled
20220130 001457 worker: -- Audio config
20220130 001457 worker: MPD conf updated
20220130 001457 worker: ALSA card number (0)
20220130 001457 worker: MPD audio output (EWCG Discrete R2R DAC)
20220130 001457 worker: Audio formats (S16_LE, S24_LE)
20220130 001457 worker: ALSA mixer name (none)
20220130 001457 worker: MPD mixer type (software)
20220130 001457 worker: Hdwr volume controller not detected
20220130 001457 worker: ALSA output mode (Default: plughw)
20220130 001457 worker: ALSA loopback (Off)
20220130 001457 worker: Reset renderer active flags
20220130 001457 worker: CamillaDSP (off)
20220130 001457 worker: -- MPD startup
20220130 001457 worker: MPD started
20220130 001458 worker: MPD accepting connections
20220130 001458 worker: MPD output 1 ALSA Default (on)
20220130 001458 worker: MPD output 2 ALSA Bluetooth (off)
20220130 001458 worker: MPD output 3 HTTP Server (off)
20220130 001458 worker: MPD crossfade (off)
20220130 001458 worker: MPD ignore CUE files (yes)
20220130 001458 worker: -- Feature availability
20220130 001458 worker: Source select (available)
20220130 001458 worker: Source select (source: MPD)
20220130 001458 worker: Source select (output: EWCG Discrete R2R DAC)
20220130 001505 worker: Bluetooth pairing agent (started)
20220130 001505 worker: Bluetooth (available: started)
20220130 001505 worker: Airplay renderer (available: started)
20220130 001505 worker: Spotify renderer (available: started)
20220130 001505 worker: Squeezelite (available)
20220130 001505 worker: RoonBridge renderer (available)
20220130 001505 worker: Multiroom sender (available)
20220130 001505 worker: Multiroom receiver (available)
20220130 001505 worker: UPnP renderer (available)
20220130 001505 worker: DLNA server (available)
20220130 001505 worker: UPnP browser (available)
20220130 001505 worker: GPIO button handler (available)
20220130 001505 worker: Stream recorder (n/a)
20220130 001505 worker: -- Music sources
20220130 001505 worker: USB sources (none attached)
20220130 001505 worker: NAS and UPnP sources (none configured)
20220130 001505 worker: -- Other
20220130 001505 worker: USB volume knob (Off)
20220130 001505 worker: Shellinabox SSH started
20220130 001505 worker: USB auto-mounter (udisks-glue)
20220130 001505 worker: LED0 (On)
20220130 001505 worker: LED1 (On)
20220130 001505 worker: Saved MPD vol level (0)
20220130 001505 worker: Preamp volume level (0)
20220130 001505 worker: MPD volume level (0) restored
20220130 001505 worker: ALSA volume level (None)
20220130 001505 worker: Auto-play (Off)
20220130 001505 worker: Maintenance interval (3 hours)
20220130 001505 worker: Screen saver activation (Never)
20220130 001505 worker: Session permissions (OK)
20220130 001505 worker: Watchdog started
20220130 001505 worker: Ready
20220130 001833 worker: Job hdmiport

[Tim Curtis]

The "EWCG Discrete R2R DAC" selection loads the rpi-dac driver which does not support Hardware volume and thus the Moode log shows the lines below. The rpi-dac driver was specified by the manufacturer as the driver to use with this DAC board.

20220130 001455 worker: ALSA mixer actual (none)
20220130 001455 worker: ALSA volume (none)