AYA II DS, DIY edition

As announced a few months ago, we have another run of AYA II.

This run, marked as DS, includes one update with respect to AYA II 2014: synchronous DEM clocking circuit is more completely integrated, so now it is not optional but integral part of AYA II project. By using BCK signal from TDA1541A input, this circuit operates properly i.e. synchronously, regardless of selected source.

PCB layout is updated to suit this change, and there are also several other minor changes on PCB, in order to facilitate mounting of possibly different parts.



The AYA II DS is sold out.



Related topics:

AYA 4: 2018 AYA release, featuring 192/384 kHz async USB

AYA II 2014 DIY edition talks

USB to simultaneous data (or I2S) board


189 Replies

  1. Avatar

    Hello Pedja,

    This is cool.. But does this also entail that the SPDIF and USB input sections of the Aya II DS be disabled for the new board to work?? Making the Aya II DS ‘purely’ a USB input dac, via the new USB to Simultaneous Data converter board?? The firmware thing where it could be switchable to I2S or SPDIF output is a bit fuzzy to me for now.. Maybe an illustration in the near future would help for us not so technically adept..

    I guess if we’re gonna have a chassis, having extra space for a new board and another transformer is a good idea..

    Thank you.


  2. Avatar

    Hello Frederick,

    You should disable only the AYA II USB stage, and connect this external USB board to U.FL connectors J301-J304 instead. AYA II S/PDIF input stage should remain available for use with any appropriate S/PDIF source (CD transport etc.).

    Existing USB stage can be disconnected by removing its output series resistors (R118/R119/R120). The stage itself can be also fully disabled by disconnecting its supply (AC1), which is recommended not only to make the chips there fully quiet, but also because that way you will have that transformer secondary winding available to feed this new board.

    I will still check the options of making this new USB board to output both simultaneous data, and I2S & S/PDIF at the same time, but the chances are it will be rather only one at the time, so either only simultaneous data mode, or (alternatively) I2S & S/PDIF mode. This board is actually meant as a PC (USB) interface designed for TDA1541(A), so having the outputs other than simultaneous data is not really the imperative. I2S and S/PDIF outputs is the option that should be understood rather as an added feature that keeps the board more “open”. For use with AYA II, it will be of course recommended to use this new USB board in simultaneous data mode.

    The only practical problem here would be that the TDA1541(A) mode in the AYA II 2014 / DS is not automatically switched between simultaneous data mode required for use with such a board, and I2S required for use with on-board S/PDIF stage – it must be done manually by the on-board switch (S3) instead.

    Regards, Pedja

  3. Avatar

    Hi Pedja

    Just for knowledge sake, Ian Canada is selling boards of similar nature I think . May I ask the difference between the both ? Goes without saying I offcourse will stand on your side cause it made especially for Aya


  4. Avatar

    Hello Pedja,

    Thank you for all the info.. I’ll just have to wait as more details about the board emerge.. Yeah, it’s great that we could save on another transformer by using the unused secondary winding for the Aya II DS’ USB input.. Noted on the (S3) manual switching for Simultaneous Data Mode.. A minor inconvenience, but if that tiny switch can be mounted off the PCB (for front panel chassis mount) without any drawbacks, then that would be cool..

    Any idea on the new board dimensions and on the USB socket placement on the board?

    Many thanks..


  5. Avatar

    Hello Jaffrie,

    I am not familiar with Ian’s board, nor did I ever had it at hands, but as far as I understand what it does is to convert between different PCM protocols. So with TDA1541A it can be used to convert from I2S (more common) to Philips simultaneous data protocol (rare), which is preferable mode for TDA1541A – please see:
    TDA1541A and Model S USB (part 2) – Simultaneous data mode.

    So, to use it with PC (USB), prior to it you also have to decode USB to some PCM protocol, which normally spells “you also need some USB to I2S converter”. In that way, to get Philips simultaneous data protocol to feed the TDA1541A from USB you need two stages, one to decode USB to I2S, and said Ian’s board to convert I2S to simultaneous data.

    And that is what in fact some AYA II 2014 / DS users did, and still do use. For some others, this turned to be too complicated. The “problem” is, apart from the old Philips CD players from 80’s (designs associated to TDA1540), and said Ian’s board, (and Audial Model S USB input stage, of course) there is nothing that can possibly feed Philips TDA1541(A) in this mode. This is also somewhat limiting factor in the Audial Model S MkIII use, in terms of its PCM direct input full utilisation.

    And that is how the idea for USB to simultaneous data converter board came. Of course, its USB part and clocks would be adequately designed too.

    Also, please note that this planned board would be made in a way to output simultaneous data protocol directly from USB decoding chip, so without intermediate conversion to I2S. In fact, I would have to change the plan somewhat to make it able to accept also I2S as input and convert it to simultaneous data protocol (as you can see from my previous answer to Klaus in the other topic). So if you would need to convert I2S to simultaneous data protocol, you would still need Ian’s board.


  6. Avatar

    @ Frederick:

    I would not recommend to wire that switch any further from TDA1541A, since those are TDA supply lines, and by doing this you will be at risk to pick up some interferences. You might notice that in the Model S MkIII the switch that changes TDA1541A mode is at back plate, but it actually only controls the switching relay.

    I am still not sure about possible board dimensions, but it should be relatively small, say something like 10 x 5 cm, or close to it.


  7. Avatar

    Thanks again for the tutorial Pedja.
    Frankly to me all this conversion is still
    beating round the bushes for the sake
    of convinience & creating more issues
    to mess up the sound. I don’t give a damn
    what others would say, me I still believe that
    we have not reached the ultimate in Red Book
    play back yet. Would be nice if your board is
    strickly I2S to simuteneous mode. That way I
    can connect either a CD transport or SD card
    player directly to AYA or can I via AYA DS ?


  8. Avatar

    Hello Pedja,

    I appreciate the detailed response.. That would be a relatively small board, nice. SMD parts helped with the economical size I guess. Thanks again.

    Best regards,

  9. Avatar

    as a private message – do you still have a board for me?

  10. Avatar

    Reply sent by e-mail.

  11. Avatar

    Just a clarifying question re the isolation transformer wiring:

    The secondary center tap which is taken to ground in your diagram: is that the power socket ground, the chassis (only) as a ground, or the pcb ground point, or could this be left floating?

    Currently I have it running on the mains earth but would like to avoid it as my mains earth has a 5v voltage sometimes.



  12. Avatar

    Regularly produced Audial DACs have an isolation transformer secondary center tap grounded to the chassis earth / ground point. This point is located at the bottom plate, near the mains socket, and it is also where the earth lead from mains socket, and PCB ground (C2 ground side, or pad next to it) are connected.

    Of course, the insulation has to be removed / scraped from the plate at that point. Ring connector (or spade, alternatively), screw and nut work fine, and you can use one ring for several leads.

    You can use such a setup also without the earth connection from the mains, of course provided everything is safe without it.

    Also, you can leave the secondary center tap to float, but this way you will have conventional 1:1 isolation transformer, and not so called “balanced power”.


  13. Avatar

    Hi Predja

    Thanks for the reply. Just to confirm the option for wiring where the secondary centre tap is connected to only the chassis – is it balanced?


  14. Avatar

    Hello people,

    whichone Isolation Transformer do you use? And is it sense or can i spare the money?


  15. Avatar

    Hi Predja

    The Standard EI transformers you supplied are EI-75 correct? I’m trying to source end bells for mine and just want to be sure as some manufacturers don’t specify the dimensions.

  16. Avatar


    If chassis is connected to the DAC ground – yes, but if chassis is floating or it is connected only to the mains earth – no. What “balanced power” makes balanced is its symmetry around actual device ground, and not around the mains earth.

    As for the supplied isolation transformer, yes, it is E-75 core.


  17. Avatar

    Hi Predja

    I guess the next obvious question is where is the best place then to take a ground connection from the PCB-to-chasis for the balanced operation?

  18. Avatar

    As said, C2 ground, or pad next to it.

  19. Avatar

    Hi All,

    Anyone had good news about their AYA integration and/or tweaks ?

    Have some tested mine with sucess (or not) ? 🙂

    Any subjectiv improvement with sourcable passive parts found till the beginning of the year ?

    regards to all,


  20. Avatar

    Hello Eldam and other Aya II DS builders,

    I’ve listened to the Aya for the first time with Jupiter Copper Foil 100V coupling caps the other day, it was playing for a couple of days at a friend’s house he installed ’em for me (mounted outboard from the pcb ‘cos of their size..) Bottom Line: These caps are like they were made specifically for the Aya DAC, they go together beautifully sonically.. Very impressive to say the least.. BUT the heart of the lifelike sound / natural tone is Pedja’s excellent design. He’s a real wizard.. I took a calculated gamble on this DIY dac and I’m very happy I did. Plus Pedja is a pleasure to deal with.. I can’t imagine how his more sophisticated finished Dacs sound if this DIY design is already this good..

    BTW, everything else is stock on the board except for the coupling output caps.. For now I’m doing some adjustments on the aluminum chassis that were locally made for me (the screw holes) .. The aluminum top cover flexed a bit after painting and baking in an oven even if fairly thick guage.. And I have to adjust or change the footers too, some loose thread on one of the screws.. I’ll post photos maybe next week or so..

    And oh, it already sounds really good with Jriver playing ripped cd’s to .wav for the USB input..

    One day Eldam, I’ll get to try your Cap tweak provision on the board..


  21. Avatar

    Thanks Frederick,

    Looking forward to see how it looks once finished 🙂

    It’s true it is a long time it has begun : 2014 and a little less for the DS version !

    Does anyone know what is the minimal input impedance the AYA II is able to load whithout the last buffer stage (with just the first OPA861 and the 110 ohms output serie resistor (shortcut protection) please ?

    I’m without the DC blocking caps and the 100k shunt résistors before the RCA plugs.

    Sorry if already asked



  22. Avatar

    Thanks, Frederick.


    There is no exact equation or relation that can tell the minimum loading impedance for such a direct I/V output, but I personally would not go with less than 10 kOhm, simply because that additional load will act as a part of the I/V conversion.

    Also, be careful when connecting this node directly: many years back when I was talking to the OPA861 designer, he told me that they found OPA861 “collector” to be more damage-sensitive than its “emitter”.


  23. Avatar

    Hi Pedja,

    Thank you for the tip. I will remember it when choosing a new Preamp (mine being the weak link of the hifi system now)

    So I assume it is more confortable to use a volume pot nearer than 10K than 100K, to setup the spl volume at home. (not using the pot in its higher attenuation position and have also a better headroom confort zone with the pot nearer to 21H00 or 24h00 position…).

    Best regards


  24. Avatar

    Usually the potentiometer value is chosen as a highest value that still preserves stable conditions at amplifier’s inputs.

    As for the attenuation levels, it is the potentiometer curve that determines this, rather than potentiometer value.

    Anyway, if you are in search for pre-amplifier, I would strongly suggest the low impedance shunt potentiometer, as used in the Model A. This would require the output buffer in the AYA II (it will drive 1 kOhm and lower impedances with no problems), and due to fixed series resistance the atenutation curve can not be fully logarithmic, but it is still the best sounding pre-amp “topology” I am aware of, and certainly the best if you can use cermet pot.

    More details on such a pre-amp / potentiometer will follow in one of the upcoming posts about the Model A.

  25. Avatar

    Thank you very much for all that.

    I have been thinking to putt a pot between the 861s but finally I don’t want to waste the good layout and grounding of the pcb ! And certainly will waste the zero trimming stability made before (I’m with no DC outputt cap conf as my actual preamp (the said weak link now)has DC input blocking caps!

    I had also a thought about putting one pott after the 861 buffer and putt a buffer again after the pot, a 861 inverted again or one of the very dead quiet of Texas Instrument/BB in unity gain… But I gave up as I’m not sure it is more transparent than my 47K ohms input Pre (a Yamaha C-X2).

    Looking forwards to read your next paper about the Model A pot input stage…

    best regards


  26. Avatar

    Hi folks,

    I stole Patrik’s faceplate layout a few pages back. Except mine obviously is in black (aluminum chassis) with a black acrylic fascia. I’m still unsure what type of feet to use. One of the hardwood feet that was made for me didn’t come out right..


    Attached file:

  27. Avatar

    Here’s the innards.. I could have ordered and used Tektronix clone ceramic type tag strips instead of plain tag strips. But that’s what I already have locally.. I also ran out of cotton sleeved solid core 23awg copper wire for the caps, so one channel has slightly shorter wires for the other Jupiter coupling cap.. Thanks..


    Attached file:

  28. Avatar

    Really nice chassis in black Frederick👍 How does it sound with those 2 extreme Jupiter caps? I would also want 2 of those, but couldn’t afford them right now.



  29. Avatar

    Hi Patrik,

    Thanks! You inspired the faceplate layout, so big thanks to you.. I made a comment on my initial glowing impression on the a few posts back (but I think it has more to do with the dac’s overall design, and the new caps were just icing in the cake in clarity..) There’s still some breaking in to do for the whole dac.. The caps were on sale when I got them, and they’re relatively affordable compared to those other high end boutique non-film caps.. I’ll most likely update my impressions one of these days when I get to listen to it with other speakers/systems.


    BTW, it would be interesting to know what kind of speakers Aya (original or II DS) builders personally use in their system.

  30. Avatar

    Very nice, Frederick.

    I prefer full aluminum feet, and some soft dampers below can be effective too.

    Eldam, I hope it will be helpful:

    Model A volume control


  31. Avatar

    Thanks for this inputt, it helps a lot.

    Because I have no clue of all these things and I don’t want to waste the nice sounding result of the AYA II. My last “bad” idea was this time to putt a Muse vdigital volume control chip from Muse after the opa861 buffer. This chip has the advantage to have only a lader resistive attenuation network but no embeded aop which are not always good at this low level of miniaturisation (while being often on the diamond buffer shematic 🙂 ). And also it seems it has on one side the numeric stuffs and the analog on the others side which is “maybe” simplier for the layout !

    Unfornatully, it says notthing about the sound quality when just embeded simply in a dac with just an output buffer ! So I prefer hundred times a solution which I know works already well with the AYA and ears certified 🙂 !


    PS not finished the casing because of that, plus the landing of a Raspberry P3 as Library management device (usb or I2S outputt, both good for the AYA II 2014 & DS edition)

  32. Avatar

    …. while the rasberry Pi is not able on its own to be Simultaneous mode ready 😉 …. but still can see an output device which can be simultaneous mode ready with uf-l outputt for the AYAs…. 🙂

  33. Avatar

    Hi Pedja,

    Thanks for the kudos and footers recommendation.. The hardwood feet (with some soft damping underneath) made for me were unevenly turned, obvious for 1 foot at least. So it was a no go even if it did sound good with them..


  34. Avatar

    Please let me know your product range and price.I need a DAC with nos TDA 1541A

  35. Audial


    There were several special, mostly DIY oriented AYA II DAC (TDA1541A) offers during previous years, and one of them is this you can see in this topic. The AYA II DAC has been however officially discontinued in 2009.

    For regularly available products, including two non-oversampling, TDA1541A based, Model S DACs [1] [2], please visit Audial online store.


  36. Avatar

    For those looking for another chance to buy AYA II DS, please check this out:


  37. Avatar

    Hello Pedja,

    Traffos arrived today, many thanks.
    I have a question please when looking the connection shematic you provided in the previous page of this blog.

    I use 230 V. So the primary and the secondary 2x 115 V are each tapered in serie as the shematic, ok. But I see the tapered SECONDARY is connected to a ground : I believed it should be floating as the tapped primary ! So where must I connect the tappered secondary of the Isolator transformer to the AYA AGND (where?) or to the Earth of the wall grid (in the case I have one) ? Or can we use the two secondaries of the isolator transformer to have a symetric voltage as the main traffo has also a main 2x115V primary. Sorry if stupid questions, total lack of knowledge about that !

    About the beaming : as it’s diy and I can : does it worth to put the isolator transformer outside my AYA wood cabinet, far from it (at one meter for instance in an iron case) to prevent more beaming on the digital front end, or is it of a non interest (non hearable) ?

    Thank you in advance



  38. Avatar

    Hello Eldam,

    You can leave the isolation transformer secondary center tap to float, and then you will have usual mains isolation (1:1) transformer. But, if you connect this secondary center tap to the ground, then you will also have so-called balanced power, with it is own benefits.

    In Audial units, this tap is connected to the chassis earth ground point, which is the point at chassis, near mains socket. The same approach usually works the best even if your home electrical installation does not include (safety) earth (might be the case with older buildings).

    Putting this isolation transformer into the separate enclosure or chamber or simply further from the other electronic, and even further from the mains voltage transformer, is always the good idea.


  39. Avatar

    Hi Guys,
    Was wondering if anyone here has a USN version ll board for sale ?

    Thank you

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