ackoDAC based on ES9018

[acko]

Hi Everyone,

I have started a DAC design based on the Sabre32 ES9018 for DIYers. I am finalising the design at this stage and waiting for parts to test this. Briefly the specs are as follows:

1. ES9018 in 2 or 8-Channel mode.
2. On-board high speed comparator for SPDIF.
3. I2S, DSD, PCM Inputs
4. Precision low jitter clock based on Crystek CCHD-950 8MHz
5. 7 Independent power supplies for the DAC and output stage
6. Low noise internal power based on LM4562 and LT1763
7. Separate ground planes for digital and analog paths
8. Polymer electrolytics caps, COG creamics and low noise thin film resistors
9. 70u thickness copper with Gold flashed pads and anodized tracks.
10. Machine soldered in an ISO9000 facility.

Note: External Micro needed for control.
External IV stage required


Also planned Bare or partially loaded boards for those who wish to tweak or source their own parts. See attached prototype pics. Any feedback appreciated.


Latest news: 20th July 2017
Updated to use ES9038PRO chips!

 

[chungtat]

May be digital POT for volume control?

 

[analog_sa]

Regulators are remote?

 

[acko]

External Micro can implement digital volume control with a switch select if this option or external volume control. This will connect to the header marked "Control". I will get this done before releasing the DAC kit. I am also thinking of putting the Micro on-board for convenience but not sure if this will upset the low noise circuitry.

Thanks, acko

 

[acko]

There are low noise on-board regulator placed very close to the DAC chip but yes pre-regulators and other power feed components are extrenal. The supply can be sourced from single feed for convenience or go for fully separate ones for best performance. I will also do matching psu boards to make things easier to setup.

Thanks, acko

 

[agent.5]

Any chance that your board will allow easy switching of input modes? I am looking for a DAC allowing more than one SPDIF inputs and I can select which input for conversion on the front panel.

 

[acko]

Yes, this can be done on board with the Micro doing the switching/selecting in response to say a push button. Will try to add this feature

 

[acko]

All Parts have arrived and NDA with ESSTECH signed for full access to design information. Board design being finalised and should go for fabrication in 2 wks. Micro design and programming in progress. Plan to incorporate Vol control, switch selects and possible PC interface for user to set relevant ES9018 registers

 

[acko]

Any chance that your board will allow easy switching of input modes? I am looking for a DAC allowing more than one SPDIF inputs and I can select which input for conversion on the front panel.

8 Channels of SPDIF now on-board. Will see if I can squeeze in the isolation transformers as well.

 

[agent.5]

8 Channels of SPDIF now on-board. Will see if I can squeeze in the isolation transformers as well.

WOW.

If you have not finalized the DAC layout yet, I am just thinking that it may be nice to add one extra tiny hole connected to the clock output. This way, people will be able to easily use the clock output as a world clock to sync something else, say a CD player or Squeezebox or whatever.

 

[acko]

WOW.

If you have not finalized the DAC layout yet, I am just thinking that it may be nice to add one extra tiny hole connected to the clock output. This way, people will be able to easily use the clock output as a world clock to sync something else, say a CD player or Squeezebox or whatever.

Ok, will add this too. Will keep this design open for suggestions/feedback for another 2wks.

 

[jkeny]

Acko,
Great to see someone else branching out & doing a fresh layout for the Sabre chips.

One thing - I have picked up that the power supplies to this chip are of huge importance & require careful consideration, particularly AVCC. Also advised to keep separate the supplies to the top & bottom padring (DVCC_T & B) - this way the clock feed does not have any perturbating activity to contaminate it!

 

[tritosine]

all i can think of is producing some "solid" connection inbetween the IV and basePCB, sorta "sandwich" structure with solid copper connectors. The rest whats needed is only the uC side, like uploading filter coefficients from PC . Also , I never saw 4 pieces of SPDIF output anywhere , but I have a Lynx aes16 that has 8 pairs of AES/ebu outputs.

 

[glt]

It would be nice to be able to bypass the micro (Have header in the I2C lines) and use external micro such as Arduino

 

[gorko1]

acko,any news?

Regards,
Goran

 

[tritosine]

maybe its the NDA thing... actually i became less and less interested since i actually try and sim 512 tap crossover filters, I suppose its the 44/48 > 88/96 stage that can be altered. 1-20khz bandpass = no chance ....

 

[orpheus]

Interesting work, thank you for taking the time to put this board together. It would be great to be able to build a DAC with the Sabre. The Twisted Pear isn't really DIY since it's already built up, and the cost is a bit high compared to ordering the parts and stuffing the board yourself.


Are the Sabre chips readily available to individuals? The last I read, they were only sold in lots of 1000.

Thanks again, I look forward to your finished product.

Aaron.

 

[gripracer]

I am totally excited about this, please tell me when the first ones are built. I will buy one.

What do you think the price for an assembled board would be?

 

[acko]

Hi Guys,

Thanks for all the valuable feedback. Sorry, I have been a bit busy with finalising this design (plus other projects) and trying to accomodate all your requests. A few more tweaks and tests to to go with the protoype but surely getting there, sounds really great! As for some for your queries:

1. Will make this as DIY as possible. You can also have the bare board and source/load components yourself. DAC chips can be bought in smaller quantities. I have got mine from Shaw Electronics, selling ~USD50 ea for 10, but you need to get NDA and proposal submitted first.

2. The IV board (in design) is separate will stack/solder directly on top of the dac board via headers. This will allow you to experiment with different IV to suit.

3. Final design will use ES9012-2Ch (instead of ES9018 -8Ch) as this appears to sound better for stereo. Unless there is request for 8 Ch version

4. Micro is external via I2C interface and has digital volume control option. Or could use Arduino etc.

5. Prices for boards, kit in progress. Plan to build 10 complete units initially. Also a custom enclosure to match

Anything else, let me know. regards, acko

 

[tritosine]

if I sign NDA Im goin to know more about the proposed crossover idea?