USB to simultaneous data or I2S converter, series 2

 

 

 

Another series of USB to simultaneous data or I2S converter board, which was originally released previous year, will be produced during the next few weeks.

The information about this design is mostly already posted into the original board topic (please have a look also at its instruction manual), so to avoid repeating the things already told, here are only the news brought by this version.

The first change is, this board will have fully local supply (a.k.a. “self-supply”). Previous version had its own local supply for clocks and reclocker circuits (of course), but this version will introduce local supply for USB decoding part as well. The actual benefits of such a solution is still a matter of debates, but it has one practical advantage anyhow: it makes the unit reset easier. As for performance benefits, it must be noted that this change does not bring measurable differences, leastways not in jitter domain. But, in order to achieve the highest possible sonic performance, here we are faced with one huge upcoming topic, and which we will discuss soon openly: it is about this and similar PC audio things, such as USB cables and conditioners, or PC software, that we still can not capture by measurements, but we can hear. (And which recalls the old topic of CD transports sonic qualities.)

Of course, this version hence requires two transformer’s secondary windings, one for USB side, and another for clocks, and they both can be anything between 7 and 11 VAC.

And second change is, other than as ready made module, this version will be also offered as ready made device, in anodized aluminum chassis with Audial logo (chassis designing is in process, estimated size is 20 x 12 x 5 cm), and with BNC connectors at its output PCM side.

Modules will be however still equipped with U.FL connectors. They will also have BNC footprints, but these will be left unpopulated. Generally, U.FL are fine as PCB connectors and wiring between the boards, while BNC are more convenient for external use.

The picture below shows the block diagram of this version of the board. Click on it to see it full resolution, please.

 

 

Output format and master clock frequencies

With TDA1541(A), a simultaneous data protocol is highly recommended. Lower master clock frequencies do sound a bit better, and in simultaneous data mode a 11.2896 / 12.288 MHz clocks are adequate for full compatibility with sampling frequencies up to 192 kHz.

In I2S, a 11.2896 / 12.288 MHz clocks will work up to 96 kHz, and for up to 192 kHz compatibility a 22.5792 / 24.576 MHz frequencies are necessary.

In addition, this board can output PCM1704 format. In this case a 11.2896 / 12.288 MHz will work up to 192 kHz, however 22.5792 / 24.576 MHz will make it hardware compatible up to 384 kHz, and this compatibility might be enabled by future software updates.

As before, the output format is set by firmware, but additional firmware chips will not be sold at this time. Firmware chips sold with first version of USB board will however work with this version too.

 

Ordering

If you want to order both the module(s) and completed device(s), or any other combination of different items, you can define one item and add it to bag, and then change the options and add to bag another item. You will be able to review and edit your order, before you proceed to checkout and make a payment. Payment is possible either by PayPal or by bank transfer.

Module price is € 150, completed device is € 410. Shipping by Airmail (registered and insured), € 17 shipping and handling fee applies per order.

We will accept orders during the next two weeks.

Once the manufacturing process starts, it will take six weeks to complete. In that way, the shipping will start in the first ten days of July. Of course, everyone will be notified prior to shipping, especially taking into account that it is the summer vacation time (for this half of the planet).

 

 

Related topics:

USB to simultaneous data (or I2S) board (2016 release)

TDA1541A and Model S USB, part 2: Simultaneous data mode

High resolution audio, async USB, oversampling, upsampling and stuff: The current state of affairs

 

27 Replies

  1. 12-05-2017

    Hi Pedja,

    would you recommend 50 Ohm or 75 Ohm connection (bnc) for simultaneous data transfer?

    Best regards

  2. 15-05-2017

    Hello Tobias,

    There is really no general preference towards either of these. In my view, and for our purpose, 50 Ohm BNC is more common, while 75 Ohm line is (a bit) easier to drive, but that is all. What really matters, once you decide to control the impedance, is to keep the whole line as close as possible to supposed value, whether it is 50 Ohm or 75 Ohm.

    So, with 75 Ohm receiving unit, such as Model S Mk3, it should be 75 Ohm, and with receiving unit that is 50 Ohm, this unit output should be 50 Ohm too.

    Still, we have here four lines, each carrying one signal, and while it can be welcome, the benefits of controlled impedance in this case is not that huge as, for instance, with S/PDIF.

    Regards

  3. 24-05-2017

    Nice that there is second run! Will this version allow a firmware change by the user through USB, jtag or other?
    Regards

  4. 26-05-2017

    Hello Berny,

    It is always possible to flash the firmware by JTAG programmer, since both previous and this version of the board include necessary connections.

    As for the update via USB connection (DFU), I need to make a couple more checks, but this time it will be most probably possible to do this too.

    Regards

  5. 26-05-2017

    Updatable by USB would fantastic news! I suppose you will make availble to the buyers the different firmwares in that case…? Look foreward to this! Regards

  6. 27-05-2017

    In case you are referring to the output format, yes, among the other things this feature would also make possible to change it.

    Still, please note that this way it is not possible to fully load the firmware, but only to “update” it. And, since there would be too many possible output format migrations (six, precisely speaking, times two, as we have two master clock set-ups), only the most typical migrations files would be ready available, while the others could be provided on demand.

    Rgds

  7. 02-06-2017

    I received several inquiries, and here is the information for those who would want to use this board with TDA1540 (14 bit) or with PCM1702 (20 bit).

    These chips use right justified protocols, so Latch Enable has to be positioned with respect to the end of the binary word. It means that the TDA1541A (simultaneous data) and PCM1704 firmware should be changed so the LE is moved to the left for two, and four bits, respectively. This is not hard to do, and can be done on request, and I can of course verify the output by the scope (and provide the screenshots), however I can not verify this with actual DACs, simply because I do not have them at hand.

    Regarding the project itself, the ordering form will remain open for the next few days, and then we are going to start production.

  8. 11-06-2017

    Sorry for this repost but I’m not sure if anyone is monitoring the series 1 blog.

    I was wondering how hard it would be to convert the series 1 into a series 2 board? If you had a clean 5v supply what would be the best – simply tying in the 5v at the usb header pin or maybe using the +/- points after FB1U1 (see underside of board)?

    Thanks 🙂

  9. 12-06-2017

    There is a bit more about actual supply re-wiring done in series 2.

    As for your idea, I have never tried it that way, but it might work too. I will try to check it tomorrow.

    (If it does work, I would skip that ferrite bead.)

    Regards

  10. 12-06-2017

    Thanks Predja

    I appreciate the reply and the effort. I was thinking of using one of the spare 9v lines I had in conjunction with the onboard PSU for one of the unused supplies. So it should be stable and clean.

    Excited to hear what you find.

    Brent

  11. 13-06-2017

    So… I will still have to look into details, but for now I can report that the idea generally does work.

    Regarding the supply that can be used here, please note that you need here completely separate supply, in a way it is galvanically isolated from both the rest of this USB board and the DAC. So, if you use some of AYA II on-board regulators for this purpose, you will have to cut the AYA PCB ground, to disconnect given regulator ground from the DAC ground.

  12. 14-06-2017

    Thanks Predja

    I’m thinking either the unused SPDIF input stage 5v regulator circuit or a standalone shunt regulator (Salas Reflektor maybe which may be a bit of overkill here).

    If my understanding of the AYA SPDIF input stage is correct then the ground there is completely separate from the USB and power grounds and is only connected when the stage is in use via the relays – right?

    Regards

    Brent

  13. 14-06-2017

    Actually, what you said applies to the AYA II USB section. At the S/PDIF stage, it is only the input transformer primary side that is decoupled from the rest of the DAC (C205 put aside), while its circuit and supply ground is always connected to the DAC ground.

    Also, please note that this USB board front end requires +5 VDC, and it draws 110 mA (typically), so the regulator should be scaled accordingly.

    Regards

  14. 16-06-2017

    Hi Pedja,

    What exactly is provided if you purchase a module. ie PCB with xmos chip soldered and flashed.
    Are all the passives, crystals, silicon, etc included?

    Sorry maybe it is mentioned somewhere already.

    Cheers

    Ryan

  15. 17-06-2017

    Hello Ryan,

    Yes, a module is also practically a working device, that takes two transformer secondary windings to operate. It does not include only BNC outputs.

    Regards

  16. 28-06-2017

    Hi Mr. Rogic:

    The USB to simultaneous data or I2S converter, series 2 board is available? If yes, please let me know how to purchase it.

    Best regards,
    Antonio

  17. 29-06-2017

    Hello Antonio,

    You have mail.

    Regards

  18. 16-07-2017

    We are about 15 days late with respect to the original schedule, but now everything is set for manufacturing, and series will be produced during the upcoming week.

    Of course, everyone will be informed prior to shipping.

  19. 23-07-2017

    One of the requests I have been receiving as this project was developing was from previous AYA II owners: some of them wanted another AYA board, so they can make real balanced TDA1541A DAC.

    So, here is the offer: during the next 7 – 10 days I will accept orders for AYA II (DS). You can order either bare or populated board (it can be with or without its own front ends, i.e. only DAC part), and transformers, so it is basically the same offer, as when AYA II DS was originally released.

    https://www.audialonline.com/topics/aya-ii-ds-diy-edition/

    There will be no online ordering for this item, so to place an order please use contact form, or send your inquiry to info@audialonline.com .

  20. 25-07-2017

    Hi Predja

    If I can be forward and make a suggestion – why not release a SPDIF splitter for a balanced TDA configuration? It could nicely tie into the UFL connectors for the SPDIF input on both of the AYA board.

    I’m not sure if it would be warranted or the demand would be enough but after much searching there doesn’t seem to be a off-the-shelf solution I could find anywhere. I’m actually busy assembling the arts based on your schematic published elsewhere on this site.

    Regards

  21. 27-07-2017

    Hello Brent,

    I understand the point, however for the time being I do not plan to release new DIY items or projects.

    Regards

  22. 04-08-2017

    hi Pedja,

    please see your personal email. Thanks!
    -phil

  23. 05-08-2017

    Hello Philip,

    Reply sent.

    Regards

  24. 09-08-2017

    Hi pedja

    I have a PCM 1704 .homebuild dac
    And would like to use the version 2 USB module for it.

    How to order?

    Br Kurt

  25. 09-08-2017

    Hello Kurt,

    You have mail.

    Regards

  26. 09-08-2017

    And now, for official information of the state of this project:

    The boards are produced, and now I am checking some details prior to shipping, which will start next week. We will ship firstly the modules, and then completed units.

    And, here is the picture of the board. This one was actually taken prior to through-hole parts mounting, so what you see is SMD only – which makes the most of the parts though.

    At left, you will notice some USB decoder supply parts, added in this version. At right and bottom right part you will notice some unpopulated SMD parts too: these are the buffers that drive BNC outputs, and their own supply.

     

     

     

  27. 09-08-2017

    Nice looking card!

    Can’t wait trying out this “simultaneous” thingy and see, or rather hear, if I can detect any differences from I2S.

    Thanks for making this available to DIY’ers.

    Regards,


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