ackoDAC based on ES9018

[acko]

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

Yes, you will find all this information in the full datasheet

 

[Gaston]

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

Personally I would be extremely interested in a 8ch version. If needed I will front some donation(paypal preferably, but I have an account with westpac) to make it happen...

Please PM if any support is needed.
Regards
/Gaston

 

[tritosine]

ok I don know how that crossover works at all , from what I gathered its simply the anti alias filter that precedes the asrc, and its 512 taps long . I don know If I want to sign that NDA. The stuff I would want, would only work If I subtract one filtered channel out of one thats phase inverted and 'unfiltered', doing that in the analog realm seems too distant and cant think of it seriously hehe.

An externally hosted image should be here but it was not working when we last tested it.

 

[acko]

Hi Gaston,

8-Ch version is not really shelved, just that 9012 being custom designed for stereo has fewer output lines and makes the physical layout neater and less criss-crossed trying to group all the outputs, so possibly that explains the apparent slight advantage during listening tests.

So both versions will be made available for release. Thanks for your support. Will contact you soon.

Also, for your information these parts can be configured for pure mono mode, taking 1 channel of direct PCM per board for really top end application. Anyone intersted?

Regards, acko

 

[NicMac]

Interested. Is the 9012 not a Vout DAC so no need for and I/V stage?
May recall wrong.

 

[acko]

Interested. Is the 9012 not a Vout DAC so no need for and I/V stage?
May recall wrong.

Output can be configured as Vout for easy interface but for best results Iout is recommended and this requires a suitable IV stage

 

[jkeny]

8-Ch version is not really shelved, just that 9012 being custom designed for stereo has fewer output lines and makes the physical layout neater and less criss-crossed trying to group all the outputs, so possibly that explains the apparent slight advantage during listening tests.

Can you say in what configuration you compared the ES9018 with ES9102 DACs? In what way did you find the 2 channel bettered the 8? This is interesting research acko & deserves more airing. Unfortunately, the 2 channel DAC chip is just as expensive as the 8, so no savings to be had.

 

[tritosine]

perhaps opamps stand 4mA better than 16. Anyway Im out , I wont sign no NDA. Also unsubscribed.

 

[kingbowser]

the ES9012 is only simpler to engineer with (if you need a stereo application). Many pins are not connected, so they can be left floating.

 

[orpheus]

Any possibility of a differential output? I believe that the Twisted Pear version of the Sabre DAC parallels the outputs of the multichannel DAC and then uses a differential I/V stage, which is appealing to me since there are not many differential DIY DAC options out there. I don't know if a lot of other people are interested in differential output, it just seems to make sense to implement it when it is possible.

Thank you for your time and work, I look forward to having a chance to buy a kit from you.

Best,
Aaron.

 

[Pavee99]

Hello Acko,

I'am certainly interested in both 8 and 2 channel version.
I would like to upgrade my Behringer dcx 2496 with the 8 channel version. For normal stereo use, i'am very interested in the 2 channel '9012' version.

However I like to know the selling price first, it must be certainly lower as the list price from TP, cause this is far over my budget.

So if the price is right i'am interested in two units, 2 and 8 channel.

Thanks in advance and keep up the good work!

 

[acko]

Hi All,

Thanks again for the all feedback. I am getting close to another build of the dac board and have added new features:
1. Both 9018 and 9012 on a single design (2/8 CH).
2. Choice of XOs either Crystek or Tentlab
3. 8 CH digital (e.g spdif) inputs.
4. 2/8 Differential outputs for IV stage
5. Improved layouts with separate psus and ground planes for AnalogL, R and Digital

As you can see the complete system includes other modules like IV stage, Micro, etc so there is still plenty of work but getting there.

I will get some pricing of the DAC boards by next week.

Thanks and regards, acko

 

[acko]

Can you say in what configuration you compared the ES9018 with ES9102 DACs? In what way did you find the 2 channel bettered the 8? This is interesting research acko & deserves more airing. Unfortunately, the 2 channel DAC chip is just as expensive as the 8, so no savings to be had.

Hi Jkenny,

Personally I found no difference in perfomance, just that a friend of mine who is helping to evaluate picked the 9012 in random A-B tests at all times based on a more spatial result with the 9012.

Technically, the output of the 9012 is easier to combine to the IV stage as there are only 2 pairs to manage. My first prototype has slightly messy output for the 9018 and this could probably explain. The application note recommends short and closely spaced wiring. Anyway, the new boards have better layout so I am hoping this will improve things.

Thanks and Regards, acko

 

[qusp]

ohhh man!! just when i'm finishing my Dual mono Buffalo32. seems you have beaten the TP guys to what is effectively the 'tweakers build' depending on price I may grab one anyway and build it up to compare and keep the favorite. seems my aspirations for my own I/V stage or transformer coupled output would be much easier to implement with this build. I suppose I could use this AND the buffalo32 in a multichannel rig, with the buffalo putting out the bass output and this doing the rest hmmmm.

 

[acko]

Price Info:

DAC bare board ~USD50
Fully assembled and tested DAC board: ~USD400

Note: These are estimates only. I will update with purchase prices and options when closer to release.

 

[jkeny]

seems you have beaten the TP guys to what is effectively the 'tweakers build' hmmmm.

Don't kid yourself, the TP guys had no intention of doing a tweaker's pcb (or let's say it wasn't a high proirity ) - but now that there's some competition ........

I don't think this is really a tweakers board as there aren't enough options for experimenting/optimising the PS which, I believe, is the most critical element for getting the most out of this DAC. Ideally, I would like each PS to the DAC chip could be kept separate & possibly combined later based on the results of experiment. I'm not sure if you have regulators on the pcb but an option to avoid these would also be useful.

 

[acko]

Tweaker's Version (T version)

Hi Jkeny,

The bare board can in some way be tweaked depending on how you mount and wire components. There are on-board regulators (LM4652s) that you could opt out and wire direct, but if you really want a true tweaker's board then consider the option (T version) as attached:

1. All separate power lines (even for DVCC_T & B).
2. No on-board regulators
3. Decoupling caps (ceramic COG) close to each power pin.
4. 100uf Panasonic FM Electro caps on incoming lines.

Let me know if this suits and any suggestions for improvement.

Regards, acko

 

[jkeny]

Now you're talking - this is moving in the rigt direction, I believe - I would be opting for the cheaper ($3) Crystek smd clocks though & not the larger Tent or Crystek ($30) parts (with a superlative low noise PS), so maybe this could be accommodated?

Where are the output connections? Is there a ground plane on the bottom of the board? Are the COG decoupling caps linked to the ground plane through Vias? It's impossible to glean this info from your pdf.

 

[jkeny]

Also, are all the supply lines & ground planes low impedance?

 

[acko]

The board layout follows recommended guidelines:

1. Solid ground planes on the bottom only and all decoupling caps have their own vias that connect directly to it.

2 Gound planes for AGND_R, AGND_L and DGND are separately laid out and joined only at a single point.

3. There are no lines cutting across these ground planes, so maintaining "line-of-sight" to the output pins.

4. AVCC_R and AVCC_L have their own power planes to respective connectors for low impedance path.

5. Board is double thickness (2oz) copper as standard, again for low impedance. If you fancy 4oz, special order.


Low cost crystal can be accomodated if you can let me know the part number/footprint.

I am planning a limited build (bare boards) for this version (~10 only) in about a week. If anyone interested can reserve by sending me PM. Price ~USD50 as indicated before. (No payment until ready for print). Final price may be cheaper as I will pass on the usual discount from my board manufacturer.

2 standard options now available:

ackoDAC-T2 BB (Bare board, Tweaker, 2Ch based on 9012)
ackoDAC-T8 BB (Bare board, Tweaker, 8Ch based on 9018)

Note: I am not running a DIY shop or business so every development is by sales proceeds, donations or contributions, so your generous support is most welcome.