AYA 5

Continuing the AYA story, we are about to release the AYA 5. We are making some significant changes with this version, and you can read about the reasons behind some decisions on the poll we had.

The AYA 5 will be manufactured in limited series, and available for ordering during the next two weeks. The shipping will start by the end of August, and most orders will be processed probably in September.

The AYA 5 will be released both as a regular, completed device, and in several DIY forms.

Since the AYA 5 includes more SMD parts than its predecessors, this time there will be more DIY options. As before, the customers will receive an assembly manual, with a parts list, schematic drawings, and all the other information necessary to complete the AYA 5. Please however note that the USB stage is not supported for DIY.

Regarding the parts, other than the TDA1541A D/A chip, the AYA 5 uses either the parts in current production, or at least the parts still available at regular vendors.

The block diagram below shows the AYA 5 overall topology and main features.

 

 

(Click on the image to enlarge it.)

 

 

So, the AYA 5 will normally have one USB, and two S/PDIF inputs: one coaxial 75 Ohm BNC and one optical. Both the USB and S/PDIF input stages can be abandoned, so the “raw” PCM signal can be sent directly to the TDA1541A instead. The PCB provides a set of U.FL connectors at both these paths, and an HDMI connector is also available (HDMI can be used only instead of the USB input).

Similar to the S5, the AYA 5 USB stage is four-channel capable, with third and fourth channel available as digital output at HDMI connector, complying with Philips simultaneous data and Audial PCM direct specifications. This output can be “looped-back” to another AYA 5 HDMI input, so two AYA 5 will act as a four-channel USB converter, just as S5.

The USB stage includes Crystek clocks, and operates up to 384 kHz. With BNC and optical input, as well as with external I2S sources, the AYA 5 operates up to 96 kHz.

Both the I/V and output buffer stages are discrete, and both employ a diamond transistor topology (you will find an example at pedjarogic.com legacy page).

And here is how it looks like, on a more particular, PCB level.

 

 

(Click on the image to enlarge it.)

 

 

You will notice the USB stage at the left, the S/PDIF at the back, D/A in the middle, and the output stage on the right-hand side. The S/PDIF stage is mostly SMD. The D/A stage employs SMD 1210 caps for TDA1541A DEM pins decoupling, but other than that uses mostly through-hole parts. The output stage supply is through-hole, but the circuit itself is mostly SMD (excepting the I/V conversion passives, which are through-hole).

Obviously, the AYA 5 has nine independent supplies.

 

 

Ordering

For DIY-oriented folks, we offer several AYA 5 options.

First, you can choose and let us populate the board with some parts to fit your requirements. These parts are:

1 – Fully working USB stage. Please note that, as before, the USB stage will not be DIY supported, so for those wanting the USB stage, this would be a minimal configuration.

2 – Fully working S/PDIF stage.

3 – SMD parts in the output stage. There are 30 SOT-23 transistors, and 30 1206 and mini-MELF resistors here.

 

 

 

 

The other possibility is to buy a board with a tested and working D/A and output stage (normally, it includes respective supplies), and you can also add the USB and S/PDIF input stages, and get a fully completed AYA 5 board. With such a board, it takes only transformer and chassis, and chassis mounted connectors and switches, to make a completed unit.

 

 

 

 

Or, you can buy a completed unit. This time it is possible to order Audial DAC in black finish.

 

 

 

 

 

See also:

USB interface and AYA 2021 editions (poll)

AYA 4 DAC

S5 DAC

22 Replies

  1. 07-07-2021

    Hi Pedja, I would like to take up a completed unit. i have 2 questions.

    1) Is it possible to customise it with a transformer couple balance output and a capacitor coupled RCA output?

    2) Will the USB Interface Card be release at a later date?

    Thanks

  2. 07-07-2021

    Hi Pedja,

    Is it now possible to use the Andrea Mori clock units with the separate squarers on the connectors of the Crystek clocks? If I see it correctly these are KR701-702, I cannot judge if the surrounding components hight will pose problems for the squarer boards. Is the footprint of both clock sockets the same as on Ian’s fifopi? Ian is building an alternative squarer board that consists of only one pcb with pins for both clock sockets so there is a more solid connection in order to minimise loose connections due to the weight and torque of the sma clock cables.

    Will the completely build unit be delivered including the TDA1541A?
    I would like an assembled board with USB section but without the crystek clocks and TDA chip.

    Regards,

  3. 08-07-2021

    @ Raj:

    There are two issues with output transformers in this case. First, the AYA 5 chassis was not planned to physically include transformers, and second, the AYA 5 output stage, even if it is very capable, was not tested in such an environment. And, taking into account the amount of work we already have here these days, I don’t think we will be able to address more custom requests at this time.

    The USB interface board (Mk3) is rescheduled for September, but most probably we will release it too. The interest in it was not as high as in the AYA, but is about sufficient to proceed with it.

    @ Supersurfer:

    I am sorry, but I had to give up on including the DIL14 footprints for the USB stage clocks in the AYA 5. KR701/KR702 are the input switching relays, and USB stage clocks are Q205/Q206. They both have the U.FL beside, so external clock sources can be used instead.

    It is generally possible to exclude some parts, however please note that without some of them it is impossible to test the board before shipping. In this case, without the USB stage clocks, I can not verify if everything is fine with the USB stage. With the TDA1541A chip it is not a problem, because this one uses a socket, so it is easy to replace or remove once the unit is tested.

  4. 09-07-2021

    Hi Pedja,

    you mention in you text, that the AYA5 with external i2s souces operates up to 96kHz. Why ist that?

    You mention as well, that only USB or HDMI can be used. What does that mean exactly? As an imput you mean?

    Best regards

    Ernst

  5. 09-07-2021

    Hello Ernst,

    This is the limitation of the TDA1541A chip, which 6 MHz bit clock input normally sets the maximum sampling frequency to 96 kHz with the usual I2S 64-bit frame, or 192 kHz with Philips simultaneous data protocol 32-bit frame. I did find a solution that makes TDA1541A work up to 384 kHz in Philips simultaneous data mode but did not manage to solve the limitation with I2S (yet 🙂 ).

    Yes, it is meant as input.

    The AYA 5 input switch is basically two inputs, and it switches between the USB and S/PDIF stage (BNC and optical input are additionally switched at the S/PDIF receiver itself).

    If you don’t use the S/PDIF stage, you can mount four U.FL connectors to have a direct input instead.

    If you don’t use the USB stage, you can have a direct input either by using four U.FL or (one) HDMI connector (Audial specs).

    Regards

  6. 09-07-2021

    Pedja, vielen Dank!

    I want to order and wonder, how difficult it will be to get the i/v right.
    I have an old BC547/557 (your design) and did some Hfe matching. TO92 thingies are pretty easy to match, crontrary to modern SMT critters.
    Would you recommend matching?

    Regards,

    Ernst

  7. 09-07-2021

    And one other question, you might be able to have an answer to.
    Many transformers, yours as well, tend to have primary cable isolators, that after a while tend to get annoyingly sticky. Currently I am housing all my DACs, and so the AYAII is my next candidate. It is so sticky, that I need to use a fabric sleeve in order to handle this. I really wonder why this specific isolating material is often used for this.

    Best Regards

    Ernst

  8. 09-07-2021

    Hi Pedja,

    Can you please confirm that I can feed the dac directly in simultaneous mode through the u.fl pads (I see 4 u.fl pads), and not only I2S, to get to 192khz samplerate? Or is this only possible through your usb stage?

    If I understand your reply correctly I can desolder the crystek clocks and add off board clocks through the U.fl connectors near the clocks? Will the board select the clock signal or switch the on board clocks on/off? For external clocks that are always on there needs to be an input switch.

    What topology are you using for reclocking the usb stage?

    How do I order the board without the dac chip? I cannot select from above 😉

    Kind regards,

  9. 09-07-2021

    @ Ernst:

    Yes, matching SOT-23 transistors is tedious. In such a circuit, matched transistors and resistors bring somewhat more consistent (measured) distortion numbers, but even without any matching, it will be good enough. I made a lot of similar circuits, and I’ve been both measuring and listening to them regularly, and probably more important is, the subjective performance anyhow does not change significantly, if any, or at least I was not able to notice that.

    As far as I know, it can be a silicone or PVC resin (at fiberglass sleeve), and it is used for safety reasons. It can become sticky over time, but not all resins behave the same. However, this is not really my area, so I can talk to the guys on Monday and get back to you with some details.

    @ Supersurfer:

    Yes, you can use either Philips simultaneous data protocol or I2S, at any direct U.FL or HDMI input.

    Yes, you can remove onboard clocks, and connect external ones to U.FL inputs beside. If you are sure you will use external clocks, maybe it is a good idea to install lower-cost Kyocera instead of Crystek, so we can test everything?

    Yes, there is a clock switch, so you normally connect both clocks, and the AYA 5 board selects the required master clock frequency. This clock then controls the flip-flops which re-clock all the incoming signals (so both the latch and bit clock, and data signals).

    Should your order options be adjusted further, it is best to send your inquiry by contact form, to get an adequate proforma or PayPal invoice.

  10. 11-07-2021

    Hi Pedja,

    Thank you for your reply.
    What are the mains transformer specifications for this board?

  11. 12-07-2021

    Hi Pedja,

    will ‘working PCB’ option include DAC chip, or will we have to provide our own?

  12. 12-07-2021

    @ Supersurfer,

    The AYA 5 requires six 9 VAC, one 16 VAC, and two windings for the output stage which should be most probably 15 VAC (I still have to tweak this part and confirm these last two voltages). Tolerances are +/-1 V.

    I would recommend 0.4 A for each winding, excepting one 9 VAC (AC1), which should be 0.6 A (or more).

    One 50 VA transformer can include all these windings, and my preferred option is to use one transformer whenever possible.

    @ Malvin:

    The working PCBs include all the respective parts, and this applies to the TDA1541A too.

    @ Ernst:

    The guys have confirmed, such resin-coated fiberglass is thermally way safer than say a classic PVC sleeve. PVC will stand something like 115°C, whereas the resin-coated option will survive at least 180°C, and will not melt at that.

    So, they advise taking it like that, and living with it. 🙂

    Regards

  13. 18-07-2021

    Hello Pedja,
    After payment has been sent and received, will the supporting documentation be supplied to enable parts collection while waiting for your shipment?

    Thank you,
    Vunce

  14. 18-07-2021

    Hello Vunce,

    The initial version of the assembly manual, which will include the parts list and schematic drawings, will be available in about ten days. You will receive this version, and all the updates, by email.

    This manual, along with the Windows USB driver, and possible firmware update files will be also available for download at this page download area (executables are not sent by email). Access to this area will be possible with the customer’s account.

    Regards

  15. 19-07-2021

    Hi Pedja,
    Sounds good.
    Thanks for the update:-)

    Cheers

  16. 22-07-2021

    Hi Pedja,

    A few quick questions:

    1. what would be the output voltage (Vrms) of the Aya 5?
    2. Does the Aya 5 completed unit come equipped with both the spidf and usb input stages?
    3. If cost is no object, and sound quality is paramount, do you see a big difference between the Aya 5 and the S5 units? When getting the Aya 5, what might a listener miss out on when compared to the S5?

    Thanks.

  17. 22-07-2021

    Hello Katrick,

    The output voltage is 2.1 V RMS, typically. It is set by the I/V resistors and, if necessary, it can be set somewhat lower or higher.

    Yes, the completed unit normally includes USB and S/PDIF inputs.

    In its topology, the AYA 5 comes closest to the S DACs. Its USB and S/PDIF stages are similar to those of S5, and its I/V stage is similar to the one used in The Model. I am, of course, familiar with all these circuits and parts, and their sonic properties, but I am also still to hear the final AYA 5 prototype – hoping to have one and possibly start tweaking it in a week or so. Then I will be able to provide the final audio characterization report too.

    Regards

  18. 22-07-2021

    Thank you very much Pedja for such a quick reply. I have been using dacs which have around 2.0-2.4vrms and in my tube setup, i find the gain not so high enough for a good drive. I have changed my output transformers to change i/v and hence raise the output voltage. Hence, i would like the Vrms to be around 3.5vrms. Is it possible to set the gain this high in the Aya5 without losing fidelity?

    I will be very keen on hearing your impressions on the final version and the comparison with the S5. Please keep us posted. I can accordingly take the decision.

    Lastly, one more thought has been bugging me and I feel no better person than you to address it – does having multiple tda1541a chips in a dac (say 2 or more chips) have any advantages over a dac with just one tda1541a chip?

    Thanks

  19. 23-07-2021

    Yes, the supply voltage headroom of the AYA 5 output stage is enough so we can increase the output to 3.5 V RMS. I am not sure how much the performance might change, but it is likely not much (quick simulation shows only a couple of dB higher second harmonic, which is a good sign).

    As for two TDA1541A, first, I generally don’t think the active parts paralleling is a way to improve their performance. Moreover, with TDA1541A the layout would be a mess because each chip requires its own DEM pins decoupling caps. On the other hand, the balanced topology may be fine, but you end up practically with two DACs.

  20. 29-07-2021

    Hello Pedja,
    Payment has been sent!
    Thanks

  21. 29-07-2021

    Thanks, I can confirm it is received.

    As for the current state of this project, it is still underway, so the pre-ordering remains possible for another week or so.

    Anyhow, you can expect to receive the parts list and schematic drawing previews during the upcoming week.

  22. 30-07-2021

    Hi Pedja,

    We look forward to hearing from you regarding your impressions of the final prototype of the Aya5 and its comparison in terms of sound characterisation with the S5!


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