Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

[kumori]

I am interested in purchasing this project but have one concern. The single ended output of 1.4V is only 70% of the industry norm of 2V. Does it come across as a 'quiet' DAC with limited dynamics?

Do not be concerned.
Wheter or not you need the full 2V output depends on the gain configuration of your amplifiers and the speaker efficiency. Do you usually use a 2V output source and still crank the pot all the way up?

 

[forta]

@hifiberry_dac.c file, line31, you can see below codes:
static int snd_rpi_hifiberry_dac_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_soc_dai *cpu_dai = rtd->cpu_dai;

unsigned int sample_bits =
snd_pcm_format_physical_width(params_format(params));

return snd_soc_dai_set_bclk_ratio(cpu_dai, sample_bits * 2);
}

That's why the rpi-dac module is more suitable here [1]. Pair it with the pcm1794a codec and then there is no need to recompile anything or mangling with audio stream in userspace.

[1] https://github.com/raspberrypi/linux/blob/rpi-4.1.y/sound/soc/bcm/rpi-dac.c#L37

 

[TNT]

What size smd components are those around the vRef?

//

 

[andyjevans]

I'm in - just bought the Rev 2, .05 board. I've been reading about all the mods and once I have the board in my hands I'll be looking at how to power it. I'm very interested in what Nige is doing with batteries. I'll be using it with a PSE 4P1L amp of my own design and Mark Audio Alpair 10 columns.

 

[mogle]

That's why the rpi-dac module is more suitable here [1]. Pair it with the pcm1794a codec and then there is no need to recompile anything or mangling with audio stream in userspace.

[1] https://github.com/raspberrypi/linux/blob/rpi-4.1.y/sound/soc/bcm/rpi-dac.c#L37

Yes, it can support 16bit with 64fs BCLK.

But I want to play 384KHz file bitperfect, so I have to modified i2s & codecs driver myself.

 

[spikestabber]

What size smd components are those around the vRef?

//

0603 for resistors and tiny caps, 0805 for the 2 vref caps per rail.

 

[TNT]

Thanks.. U got 0603... :-(

 

[forta]

But I want to play 384KHz file bitperfect, so I have to modified i2s & codecs driver myself.

To get it done right there is more to do with ALSA code.

 

[mogle]

To get it done right there is more to do with ALSA code.

I2S of raspi board with my driver can support 384Khz ouput, the signal captured by logic analyzer is just as bcm2835 data spec.But I am not satisfied with the sound @listening.
Do you have some advises?

Thanks!

 

[GeBa]

What about the sound of this DAC

first: please excuse my poor english...

Is there anybody who can tell me about the sound quality of this DAC compared to a Buffalo, Mambo or any commercial DAC?

I am very interested in the Soekris, and there are lots of technical descriptions and documents about it. But there is no description about that what i need to make a decision: What comes out of this device?

Regards,
Georg

 

[GeBa]

first: please excuse my poor english...

Is there anybody who can tell me about the sound quality of this DAC compared to a Buffalo, Mambo or any commercial DAC?

I am very interested in the Soekris, and there are lots of technical descriptions and documents about it. But there is no description about that what i need to make a decision: What comes out of this device?

Regards,
Georg

 

[randytsuch]

So I tried to connect my Amanero last night, but no go

Could not get signal lock, or any output from the dac.

I've been using this Amanero with another dac, and it works fine there, and the PC was talking to the Amenero ok, so not sure what's wrong.

I connected I2S data, bit clock and lr clock (frame sync), iso ground and 3.3V per the diagrams (used hifiduino blog for connection info), and double and triple checked all connections.

I had updated to latest firmware before starting.

Is there any tricks to getting an Amanero to work with this dac?

Randy

 

[forta]

I2S of raspi board with my driver can support 384Khz ouput, the signal captured by logic analyzer is just as bcm2835 data spec.But I am not satisfied with the sound @listening.
Do you have some advises?

Thanks!

Post your patch at alsa-devel mailing list to get it scrutinized.

 

[mogle]

Post your patch at alsa-devel mailing list to get it scrutinized.

My problems is how to improve sound quality .About alsa driver, all is in kernel docs,it's simple & clear; and I get 384KHz i2s as bcm2835 datasheet.There is no problem in I2S output signal for now.I can't find anything else left for ALSA-dev to do,the next will be how to figure out the problem of sound listening,I thinks so.

 

[randytsuch]

I have lock, and music, reloaded 0.99, and now it works great.

Not sure what happened. I had loaded .99 and then a filter before I connected the Amanero and couldn't get lock. This time, I just loaded .99 and left the default filter in, and it locks fine.


Randy

 

[xxxbugxxxx]

@ mogel

Can you share your patch so we can use it too?thank you

I2S of raspi board with my driver can support 384Khz ouput, the signal captured by logic analyzer is just as bcm2835 data spec.But I am not satisfied with the sound @listening.

Do you have some advises?



Thanks!

Sent from my iPhone using Tapatalk

 

[mogle]

@ mogel

Can you share your patch so we can use it too?thank you

I'm glad to share the codes:


1.follow raspberrypi office kernel buding steps, download load kernel source & building tools:
https://www.raspberrypi.org/documentation/linux/kernel/building.md

2.download my modified files from cloud disk,
my work was based on rpi-4.2.y branch, it should work on default branch(rpi-4.1.y)
link: http://pan.baidu.com/s/1dD2oe9V password: tadn

3.merge the differences from my files to the same files under same dir

4.build & install to sd card

5.add below line to /boot/config. txt on SD card, reboot & enjoy the music
dtparam=i2s=on
dtoverlay=dam1021-dac

Regards!

 

[mkliu]

I have lock, and music, reloaded 0.99, and now it works great.

Not sure what happened. I had loaded .99 and then a filter before I connected the Amanero and couldn't get lock. This time, I just loaded .99 and left the default filter in, and it locks fine.


Randy

I have the same issue when i have some older filters for v0.9 loaded.either you reload the firmware or just the right filter would be fine. Enjoy the music.

 

[TNT]

0.9 filters don't work in 0.99.

//

 

[wkw9811]

All ready, except long awaited DSD FW