USB interface and AYA 2021 editions [poll]

According to the feedback we got recently, the interest in these projects may have re-emerged. And in case it can reach 30-40 units per project, we are going to proceed with the given project and release it, as limited series.

Both these projects would be current developments of the previous ones, so those not familiar with them are advised to check them out. (The links are below.)

The USB interface board would now support multichannel operation (no worries about the usual stereo operation, it will work straightforward), and will output Philips simultaneous data or I2S protocol. Other than the set of U.FL, it would include also an HDMI output connector, complying with recent specifications set with the S5 DAC release.

The AYA may be available in the form of the DIY project, whether as a PCB with a pre-mounted USB input stage, or as a completely mounted PCB, and it can be available also as a completed unit in chassis. Will we keep the AYA project DIY friendly, or change it to better suit machine assembling, will depend on the interest. Also, it may and may not become “5” this time, it is on you. The S/PDIF receiver could be replaced with the currently active part, and other possible changes, with regard to the AYA 4, may include more inputs or some tweaks in the supply. You can post here your requests, ideas, and comments.

The price for the USB board would be €150–200, depending on the clocks used. The AYA prices would be similar to those of AYA 4, so the PCB with USB stage would cost about €200, completely mounted AYA board about €600, and completed AYA unit about €900. Shipping by Airmail (International Priority equivalent) for these items would be €15–30.

Please note this is a poll only, and for now you can not actually place an order. If we indeed proceed with some of these projects, and you have signed up, you will be notified by e-mail, in the next two weeks or so, and then you can place an order. All the items would be shipped in August.

You can sign up for more projects / options.



2021 limited editions




Previous projects:

USB to simultaneous data or I2S converter, series 2


39 Replies

  1. 02-06-2021


    Good news, count me in for an USB-AYA pcb- . It will be a good upgrade from my AYA 2014 edition I daily listen to.

    Any novelty on the buffer stage and or I/V ? Discrete . good news oaps as buffer but still w/o feedback as some new : oap 1656 (double), oap1641 (simple as I/V), list became huge these last years.

    Many thanks as a diyer enthusiast 🙂 that can not afford the model 5. and still have caps tweaks.

    PS : do you believe there could be a little 30 pcb interest for a TDA1540 version : some are playing with it those days on a famous diy forum !
    But maybe the sim mode is not the same between the TDA1541A and the TDA1540 ? At least I could ask there if you mind.

  2. 02-06-2021

    Yes, some new opamps have amazing specs, however there is only a couple of opamps (or rather “opamps”) that can work without the feedback. Generally, to have them operate this way, they must expose their transconductance node (so basically unbuffered output) to the outside world.

    The existing AYA I/V and buffer stages based on the OPA861 without feedback are simple and sound great. The only thing I would consider changing here might be the supply, as the TL431 based shunt might be kinda outdated.

    I am sorry, I have no plans to design TDA1540 DAC. The protocol as such is however practically the same, the only difference is the Latch, which must trigger after the 14th bit, per TDA1540 specifications. Some time ago I did make some USB interface boards programmed this way. Still hope to hear from the customer if it worked or not.

  3. 02-06-2021

    With the Aya 2 2014 I use only a 1K ohms I/V resistor as I don’t need too much gain and indeed it sounds good to me, I confirm that; and stable : no local opa861decoupling if I remember… it works very fine.

    So the analog stage discrete reg will be new on the AYA 4 “2021 edition” ? No TL431 but something diode based perhaps ?

    I had hope for the TDA1541 with a XMOS 16 bits compatible enhancement for the 14 bits as made by Philips with the 7030 chip… well maybe one day 🙂

    Thanks Pedja.

  4. 02-06-2021

    It was just a thought. If I was supposed to improve on the output stage, that’s what I’d rather do.

    It is not that these regulators are any bad either, and you might also remember the time, maybe two decades ago, when TL431 was all the rage. It is a shunt finally, and this configuration has a low impedance across the wide bandwidth, and I would subjectively describe it as very dynamic.

    What you may not like about it is its 1/f noise. Zeners do work better in this regard. Funnily enough, they are often lower noise than the majority of industrial so-called low noise voltage references. And by lowering 1/f noise, you get generally more natural sound.

  5. 03-06-2021

    Hi Pedja,

    Would it be possible to make available PCB with simply one or two I2S inputs then PCM>1541A with DEM synch circuit to be used (or not) and associated power supplies.

    If there is one change I would make to my system, it is to remove USB input. And output stage is easy and fun to experiment with. In fact the ‘future proof’ PCB would be simply I2S>PCM>1541A PCB.


  6. 03-06-2021

    Hello Derek,

    Conversion between serial PCM audio protocols is out of the scope of these projects.

    Also, in my opinion, even if Philips simultaneous data protocol is a preferred mode of operation for TDA1541(A), it is not that better to justify additional processing at this line. If you have a quality I2S signal, it is better just to send it to TDA.


  7. 03-06-2021


    Maybe it will be time to consider some little plus as the pcb is 7 yo today ?

    Just some ideas:

    – discrete diamond stage or buffer : up to the diyer to sort out the matched pairs… it became pretty common on the big audio diy forum.

    – CRC filtering both of the main and usb power supplies
    – 10 V between the +/- 5V of the tda1541 (but with the fast nowadays discrete scheme)
    – filtering the LT341 by a close // KP wima film cap or a tin foil styren + a big good lythic in the 1500 uF range à la panasonic FC to avoid coloration ?

    – clock DEM scheme by Rotel (public domain now ?) I do not use the actual on the 2014 after many tries.

    -giving up the Rubycon ZA caps of the analog stage for Panasonic Fr or else :well just a BOM anyone can do himself, but goes towards the DEMNING wheel principles of continuous improvement as you ask.

    – ah maybe near the crystal area : clock conectors to input a master clock or directly instead the crystals, some pretty cool low phase went into the diy world few time ago. Btw the crystek can also reacts better with pen or acrylic caps as decoupling in // of the C0G : anyway all but ceramic class 2 that are annoying.

    No ideas more,but hopes it can contribute as we did withthe uf-l connectors 7 years ago which was a big versatile plus 🙂

  8. 03-06-2021

    Hi Pedja,
    Finally! I’m so looking forward to the USB interface board. Hope you will also provide the necessary cables to connect to the Aya Dac board.

    For the Aya PCB board will HDMI input be provided? Also if it’s a complete dac , will you be able to provide transformer coupled balance output as and option?


  9. 03-06-2021

    @ Eldam:

    Actually, I did some changes with the later AYA 4 board. The USB stage has been completely changed, and S/PDIF used more SMD parts. Now, my question is, can we move even more significantly towards the SMD, with such a DIY project? Or will such an approach require to offer the board with pre-assembled SMD parts? At least all the SMD passive parts?

    Regarding supply filtering after the rectifiers, I always prefer, if it is possible, to start with resistors.

    Adding footprints to facilitate local caps bypasses is probably not a problem. Also, you can always put two SMD caps into one footprint, by mounting one on top of another. And sure, it is up to anyone to use their preferred passive parts, so long as we talk DIY.

    BTW, I recently did abandon Rubycon ZA in the S5, in favor of Elna Silmic II. And I really did not like Panasonic FR very much for the analog stage supply decoupling. Also, the S5 does not use synchronous DEM clocking. (I plan to post more about some S5 design points soon to the community forum.)

    As for the output stage, it really was not my plan to change this part of the AYA. And OPA861 is exactly the diamond structure. Yes, you can get better linearity I/V stage by discrete design (the one I published almost 20 years ago is one such design), but this output stage is a notable part of AYA II – 4 identity. I would really have to think about this, prior to making any changes.

    As for the clocks, if we can agree on some effective way to connect the external clock sources, that would be fine. If it takes one TH pad per connection, that should not hard to add. If we have to add some connectors at this point, that would be a compromise with layout, but it might be still acceptable, if the connector is small enough.

    But as I said, the main question now is: how about the SMD parts? I mean mostly SOIC packages, and 1206 and some 0805 passives. Are they acceptable? If they are, or we can come across some agreement about what should be pre-mounted, then we can add more things.

  10. 03-06-2021

    @ Raj:

    One of these above-mentioned “more things” could be more inputs, so the new AYA can also have a direct input via an HDMI connector, like S5.

    Connecting the USB board with AYA II DS would take four U.FL cables. If you can not find a source, and we proceed with this USB interface project, please remind me about this when you place your order, and we’ll add a set of these cables to it.

    For now, I didn’t plan to add transformer-coupled output as a regular option for AYA. But we will add this as an option to the poll above, and see if there will be more interest in it.

  11. 03-06-2021

    Of course I can just talk for myself, but SMD soldering till 0605 size is faisible, also soic shift register, it asks just a lot of flux. But as you pointed out with the last AYA4 USB evolution : all the sensible more little or hard XMOS chips needs to be soldered by Audial, that’s my point, not a truth.

    Well for the opa861, if I understood your paper people still uses & till recently with ad1862 for instance : you need more than hundred of each transistor to match them close to 10% only, so indeed it’s not as casual and certainly a bad idea from me. Anyway it can be made on a verroboard or little pcb as well, people became more active with pcb printing due to the software on line and low costs.

    So the real improvement about the DIY versatility could come from the clock. But I'”m very not the guy able to answer due to my low casual technical level. But if people are lurking here, there is a thread by Andrea Mori about good enhancement on low phase noise clock inspired by what Jocko Homo liked to do, but this time with very good SC-Cut crystals and as I said there is kits to solder adaptors he made instead the CHHD-957. So simply those guys whom also likes the TDA1541A a lot maybe curious about the opportunity to improve the already good simultaneous mode embedded since the AYA 4 on a same PCB.
    Just a feeling. So maybe some lurkers should give more ideas. Again if 7 years ago I really asked for the uf-l pads for both the I2S and sim mode, this time about clocks layout it’s far above my head. I just don’t know how… diyers todays uses crewable connector for clocks… some others don’t and stay uf-l cables… more fragile but also less expensive.

  12. 04-06-2021

    The whole USB stage is out of the question, it will be pre-mounted and not a DIY part of the project.

    I don’t think such a close transistors matching is really necessary. But, if we go with discrete I/V, I’d really like to have it all SMD, which spells also SOT-23 transistors.

    Also, will look for the options for clocks connections. Guess it will be possible to add a U.FL footprints there.

  13. 04-06-2021

    Hi Pedja,
    I too support Eldam’s idea of discrete I/V stage and adaptor for the clocks It will allow fellow DIYers to play with different clocks.
    As for the I/V stage, you mention that you are not a fan of tube output stage possible to offer some pads that can be connected to tube stage from the Dac output stage for those who would prefer this. (More option to play with!)😁

    As Long as the diamond buffer I/V stage is discreet but need to be in SOT -23 package, I don’t mind.

    Ps still looking out for your R2R Dac plans.


  14. 04-06-2021

    Hi Pedja,

    So the DAC PCB would be USB>I2S>1541A and not simultaneous data to 1541A at all?. Okay. But please change your mind 🙂


  15. 04-06-2021

    Dobro Pedja,

    My friend direct me and happy to be here again.

    Good to see some stirring and conversation.
    If you would ask? my input,.. well I think many have good already USB to I2S or SD card to I2S, or USB to simultaneous mode even. Australian guy with I2S to Sim data then 1541A DAC and they *love it*, from what I read, and I can only take one person.. but for his word, he likes more AYA.

    I question why, (and even if this subjective is not without bias) – and I look at what he do different from what we know/do. fDEM /2 within audio band, I think not good idea.. so something else fixed 10V between -15 and -5v (this guy uses a different voltage reference arrangement – completely different from what regs, or what caps, the architecture is different – and I think we should focus on that).

    After all that, surely to feed DAC with simdata direct on board and not have to ‘jumper in’, blah

    Kind regards,

  16. 04-06-2021

    sorry – he likes it *more than AYA*

  17. 04-06-2021

    Welcome back, Shane.

    It looks like many of you would like to see the AYA project moving forward. So, let me think a bit more, I will try to draw the complete picture, and see if this time we can go with discrete I/V and possibly improved supplies.

    @ Raj:

    Yes, I can add the pads to the TDA output, so you can use external I/V.

    @ Derek:

    No, the USB stage output is Philips simultaneous data. But there is no conversion from I2S to it.

  18. 04-06-2021

    So about Clocks: as you use the Crysteck package with DIL vias, there is finally no need for futher uf-l or else injection clocks entries.

    The cool very low noise phase project of the other forum should feet according his author. Anf if no room for his new pcbs that are a little bulky cause have squarer embeded, then the oldest adaptators of his previous project will feet as they have the same size as the CHHD lapteck package !

    Nothing to do more 🙂

    Sot discrete with the modern bjt low noise will be awesome if a sounding improvement… all smd, with Sussumu resistor or good Philips smd carbons… cool ! I had always a problem to choose between the old 328 that performed very low noise but the BC550 that were better in the low end only at the sacrifice of the upper frequencies over the 328 family if I remember what I read a long time ago: trade offs. The newest soic are certainly better

    About simultaenous mode and uf-l : a crazy idea maybe,I’m not a tech : I2S ufls inputs possible also just before the simultaenous XMOS stage . I don’t care myself but think to the guys that use SD trans card readers and that don’t want to hear about anything else but whom avoid the good simultaneous mode ???? Well finally an input masterclock to rule them all… lol. It begins to be too much complex, sorry for that. Let stay casual 🙂 Of course the close uf-l near the dac chip are still welcome for us crazy diyers.

    @ Shane,

    happy to see you there, quite a long time since 2014 Aya project and pm between me, you and CFT (Cheung F. T.) that landed here 🙂 on Audial. Thanks again to Pedja to have done that possible. TDA1541A is my daily dac still !

  19. 05-06-2021

    Hi Pedja,

    That’s great, simultaneous data to 1541A.
    So USB straight to this mode and not converted to I2S.
    So really no place for I2S input anywhere .. cant use external FIFO buffer (would I miss it at all?).


  20. 05-06-2021

    Hi Pedja, this is excting news, count me in, finally!

    My requests; perhaps unrealistic:
    optical, coax and AES inputs
    volume control (ideally I’d like to go straight into my power amp)
    balanced outputs.

    Or maybe a different device that could do that.

    Let’s see.

  21. 05-06-2021

    P.S. I’d also been following Asta news as it would provide volume control and balanced outputs at a similar price, but I’m guessing an Aya would sound different/better in a TDA1541A vs ESS Sabre duel?

  22. 05-06-2021

    Thanks Pedja, it will be interesting to see what you guys come up with.

    @ Eldam, good to see you here as well, its been a long time.

    Kind regards,

  23. 05-06-2021

    Hi Pedja

    My personal wish: I’d love to have a USB interface PCBA with inverted simultaneous outputs for balanced TDA1541A’s and the option to fit connectors for external clocks.
    Thank you for continuing to entertain us tinkerers!

    Best wishes Simon

  24. 05-06-2021

    @ Eldam:

    All the AYA DACs since 2014 had the optional U.FL direct input, and I would keep some sort of the direct input this time too. So, there would be either again the set of U.FL at PCB, as an optional feature, or an HDMI connector at the backplate.

    @ Derek:

    The USB stage is a master device, so I see no use for FIFO here.

    @ Alec:

    Coax (BNC) input is understood, and I will look to add the optical input too. Not sure about the AES/EBU XLR. Also, the space is tight.

    For now, Asta will remain the only Audial DAC with volume control.

    Also, the AYA remains a “single-end” (unbalanced) topology. Raj already asked about the possibility to add the output coupling transformers (among the other things they do, they can also provide balanced outputs), but we are now possibly changing the output stage, and I rather would not think about output transformers unless it is clear what is going to drive them.

    AYA vs Asta – they are different. Asta official release somehow took additional months, and once it is officially available, I will post more about its sonic properties.

    @ Simon:

    Yes, it would be possible to include inverted data outputs for simultaneous data protocol, so the USB board can drive balanced 1541 DAC. Previous USB boards had this feature.

  25. 05-06-2021

    @Pedja – understood; maybe a new Audial product idea down the line could be a stripped down pre-amp / buffer with volume control similar to that within the A20; maybe even having single-ended and balanced conversion and I/O

    I’d need something similar for the Aya as I don’t have/use a dedicated preamp currently.


  26. 06-06-2021

    @ Pedja with I2S direct input at 1541A (re answer to Eldam question), is it possible to have that I2S input somehow before the simultaneous mode drive, in other words external I2S input converted to simdata and then to 1541A?

    Kind regards,

  27. 06-06-2021

    @ Alec,

    Yes, I do have plans for such a pre-amp. But it will still take some time. No ETA for now, but it is better not to expect it this year.

    @ Shane,

    Sorry, but as I already answered above, this project will not include conversion between the PCM audio protocols.

  28. 06-06-2021

    @ Derek,

    FWIT : you still can use fifo device before via the uf-l pads. i asked them for that purpose in the 2014 edition. But IanCanada I2StoPCM has some issue for the simultaneous mode. And there is FIFO and FIFO if you know what I mean… I tried them all.

    I asked above this time a possible room on the pcb to use Andrea Mori adaptators about his low phase noise clock as a possible option to provide a sota clock to feed the USB stage output. Andrea M. is using the trace of the Crysteck clock for his adaptators for IanCanada stuffs. My understanding is it should be ok if there is room enough on the pcb of this new edition : pcb traces the size of the CCHD Crystek package, no vias so no DIL adaptors that btw are bads for clocks purposes. With A. Mori, there is no needs of a FIFO as there is no jitter injected the way the design is made. But don’t forget than PCM dac chips are less sensitive to the jitter one beleives and it’s also my experience the Aya sounds really good without Fifo and long uf-l wires everywhere VS close crystals on the PCB.

    Volume pot : well one can uses Muse electronic volume kit perhaps…

    Hope that helps and sorry for the off topic

  29. 07-06-2021

    @ Pedja

    No problem 🙂 .. is there a block diagram of AYA functionality so that I can better understand. Also, data is reclocked after the USB isolator with clock local to 1541A ?.

    Kind regards,

  30. 07-06-2021

    @ Pedja
    re: clocksDIL14 footprint: on board power supply will be able to supply the initial current required for OCXO types?. (ie. Pulsar clock: 3v3 at 150mA max for 120sec).

    Possible to provide external power to clocks?: seperated (open) traces on clock supply line(s), jumper select for internal or external power and a set of thru hole at the appropriate junctures for ext power connect to PCB – then simply move jumper one position to connect/disconnect = select int/ext clk power.

    Kind regards,

  31. 07-06-2021

    Re: power supplies – and back to previous comment on ‘D3 1541 DAC’ (google), the regulated 10V between -5 and -15V.. as you acknowledged to look further into.

    Also, I found a really notable difference for the better with additional PS filtering in the AYA for 1541A supplies that no-one talks about (?). AMR guy suggest I put additional filter, so I follow his recipe and it was rectifier – common 10R – [*new*cap – common L] -main AYA reservoir cap.

    All for good, hope we can push this to the limits but I fear we will tread close to your commercial products, so with respect for that – I dunno.

    Kind regards,

  32. 07-06-2021

    So, here is the block circuit drawing proposal for the prospective AYA 5.




    (Click on the image to enlarge it.)

  33. 07-06-2021

    As for the clocks and their supplies, I am not sure what would be the goal in this case. To use external clocks with on-board supply, or to use on-board clocks with external supply?

    Anyhow, the clocks’ supply is normally available at their pin 4 (and Gnd at pin 2). It is not designed to provide 150 mA, though.

    Regarding the -5 VDC and -15 VDC TDA supplies, they will be done exactly that way, so like -5 VDC and -15 VDC. Also, the passive supply filtering will remain one stage common mode RC, at each line.

  34. 08-06-2021

    And, here is where we are currently at.

    The interest in the AYA looks fine, and we are going to proceed with it.

    It will include several changes, so it will be AYA 5 this time. It will have a discrete output stage, and the S/PDIF receiver will be replaced with the currently active CS8416. There will be more SMD parts than before, but there will be also more DIY options, which would include some or most of these parts pre-mounted.

    All this also means that I will need some more time to design it. As I am currently designing the new amp, which will take another week or so, I will start working at AYA 5 as soon as this work is done.

    As for the other parts of the project, I think we have an idea about how the clocks will be done, but I would still like to hear more about what sort of inputs you need.

    The form above remains unchanged, so you can still sign up, to receive the notification once we start accepting orders.

    As for the USB interface board, we still need some participants to proceed with it.

  35. 09-06-2021

    Thanks Pedja,

    Re: clocks, I cant speak for others, but for me it would be option for external power to the onboard clocks so to accommodate the heated/oven type.

    Kind regards,

  36. 09-06-2021

    A splited trace with a zéro ohms jumper for the powersupply ?

    The ground can easily be kept from the pad of a close cap to ground?

    For all those clocks they indeed have their own external power supply.
    One can also do it diy : cut the trace on the board…if need to use again a solder drop is just fine…

  37. 09-06-2021

    Thanks Pedja,
    For PSU. Ok. Understand – just trying to help ‘push forward’ the design but understand now. Okay, take care Pedja.

  38. 09-06-2021

    These clocks are supplied by a SOT-23 transistor, and RC filter to each clock. Generally, these resistors (i.e. their removal) provide access to the clock supply, in either direction.

    I will think about the possibility of replacing this output transistor with a higher power device. There are nice TO-92 parts that can work here and provide above said 150 mA for a couple of minutes. Things may get more tricky if you actually need 300 mA (150 mA x 2 clocks?).

  39. 13-06-2021

    Thanks for Release Aya 5 ,
    Pls Count me in for four stero complete board (one without usb board ) for differential .
    Complete board $600 and may I know without USB board price tag .


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