ES9023 DAC + BeagleBone Black = great sound

[Oystein]

I started with a BeagleBone Black some years ago and did some mods to my Lindemann DAC to be built together with the BBB in a single box, see:

My BeagleBone Black + integrated DAC music server / streamer project page

 

Recently I had some issues with dropouts and cracks in the sound which I contributed to the DAC.

Looking for a fix I needed another DAC board so I purchased the Sellarz DAC based on ES9023.

 

The Sellarz DAC is designed to fit on the BBB.

For now I mounted the boards with the connectos outwards for easy access wiring the boards for the initial test.

 

I connected from BBB P9 pin 1 + 5 (5 Vdc) to DC in on the Sellarz board.

Connected I2S from BBB P9 pin 28, 29, 31 and 43 to I2S in on DAC board.

Connected Line Out, DC plug to external P/S and power on.

 

I could connect to MPD but no play.

I remebered if the BBB can not connect to DAC via USB nothing will play.

I had to tell MPD to play though HDMI (were the I2S signal is tapped) so modified mpd.conf to hw:0,0:

 

#

audio_output {

type "alsa"

name "I2S Sellarz"

device "hw:0,0" # optional

mixer_type "hardware" # optional

# mixer_device "default" # optional

# mixer_control "PCM" # optional

# mixer_index "0" # optional

 

And pronto ... music ... I did not expect it to be that easy but it works fine.

 

I have some ideas about an external dual clock 22.579 / 24.576 but I am happy for now.

 

Click on the pictures for bigger size ...

 

 

 

 

[Oystein]

In the meantime I have been reading a lot of the Miero BBB Botic driver topic at DIYAudio and understand I can also use a single external clock for example the 44.1/88.2 files and still use the internel BBB clock of 24.576 for 48k and multiples.

 

Using only the internal clock like I do now all 44.1 / 88.2 files are resampled to fit the 48/96k samplerates.

To see what really happens I took my osciloscope and measured the MCLK and LRCLK from the BBB to the ES9023 DAC.

 

It seems that all 44.1/88.2 files are downsampled.

Http radio, MP3 and 44.1 are dowmsampled to 32k and 88.2 is downsampled to 48k.

 

This is the Word clock (LRCLK) of a resampled file at 32k:

 

 

To avoid the downsampling I modified mpd.conf and set to resample everything to 96000:24:2 which resulted in all files playing at 96k.

As it was already late yesterday I only could listen for a short period after that but my first impression at http radio is a more direct and livelike sound.

Not bad for 128k streams.

 

As I happened to have a Tentlabs XO2.2 with 16.394 clock which I used in my CD player until some years ago I realise with Botic I can use this single clock as external 44.1/88.2 clock and still use the internal 24.576 for 48/96/192k.

 

A 16.394 clock might be a little low for 176.4 files but as i do not have any 176.4 files I will work with this frequency.

I can Always change the element to 22.579 later if needed.

 

To be continued ...

[Panelhead]

This is the wrong website for these discussions.

[Oystein]

I am just telling what I am doing and what is achieveble with some of the shelf parts.

You would be surprised how many here are really into DIY and modding electronics for better results.

 

Otherwise the whole discussion for example about modding an UpTone Regen would be banned here too, I hear nobody compaining about that.

[Qhwoeprktiyns]

This is the wrong website for these discussions.

 

You can discuss assembling a CAPS PC and tuning the supplies, disks, os, etc... But not this?

No one is forcing you to read this, and as far as I can see you are not a moderator.

[Panelhead]

I was kidding. We need more discussion of technical details.

I have particular interest in improving playback of low bit rate feeds. Listen to Internet radio and over the air HD radio. Both are low res, the HD radio is better right now. Would love to get better sound off the internet streams.

Software instead of hardware maybe the answer in my current system setup.

[Oystein]

The available options for your http streams are of course related to your hardware and software.

[Oystein]

I guess I better rename this topic to: "My BBB streamer + DAC build" ;-)

 

I have put all the components on a piece of shelf so I could work with the brick type 12V instead which I already used with my previous system.

 

I also included the Tentlabs clock as I will need this too when I have figured how to set up the Botic driver properly accepting the external clock for 44.1/88.2 music.

The tentlabs works on 12Vdc and has an onboard shunt regulator for delivering a clean supply to the clock.

The BBB + DAC needs 5Vd which are now fed by a LM317 regulator.

The power supplies will be more low noise by shunt type regulators foor BBB and DAC but I had the LM317 available for now.

 

 

I have already ordered an aluminium enclosure with semi heatsinks so I can mount the future voltage regulators to the sidewalls which will have moderate dissipation for running cool enough.

 

[Leonard]

Nice photo's Øystein! Quite an interesting project you have started here.

Very curious how this solution will perform compared to a 'traditional' PC based streamer set-up. It doesn't need noisy SSD/HD's and fans and also the power requirements are relatively low. Besides that, you don't have to invest in a separate USB card and expensive USB cables. :-)

 

Keep us posted!

[Oystein]

As this is a work in progress I am already looking forward with some new ideas ;-)

 

Looking at network connection and isolation I was thinking what can I use to achieve that.

I already have a Baaske NI-1005 LAN isolator but would completely avoiding a LAN connection and use wifi give better results?

 

I have a Wifi extender / wifi bridge / acces point model EX2700 from Netgear.

 

 

A very compact unit which plugs directly in the power socket.

Could I use the internal board and have it fed by a dedicated clean power supply and somehow integrate it in my setup ?

 

To see what is possible I had to take it apart = destroying the housing ;-)

As the unit only costs 25 Euro it is worth the experiment.

The internals are 2 PCB’s, a power supply section and the “Wifi/LAN” PCB.

The power is fed through an 8-pin connector although they are grouped as 4 pins are ground and the other 4 pins are 3.3V.

 

The wifi PCB is only 5x6 cm.

 

 

 

 

I still need to connect it to a clean 3.3V power supply or even a shunt regulator and connect it to my Beaglebone with only a few cm LAN cable … I guess I can even use an ISDN type flat cable for this short distance which will be easier to make a tight bend.

As I still need to make the new enclosure I can put the antenna(’s) outside the box. Maybe even one antenna will do for my application.

[Oystein]

Some time has past already but finally yesterday I put the DAC board in an aluminium enclosure which is put in a bigger enclosure.

Like having a vault in a building ;-)

 

This way the DAC board is isolated from most HF radiation, I even put a ferrite core around the I2S signal cables.

The P/S modules are only for the time being, for the BBB I will build a better regulator and the DAC board will be fed by a 2 sets of 18650 Li-on batteries (one charge; the other discharging and vice-versa) to have the DAC completely isolated from the power supply.

 

The Wifi board is not integrated yet and I need to do some testing to see if it gives any improvements ... soundwise and convenience / stability.

 

Short story: from wood to aluminium ... enjoy the pictures :-)