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MDAC First Listen (part 00110100)

Discussion in 'audio' started by JohnW, Dec 12, 2016.

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  1. JohnW

    JohnW Trade: Lakewest

    It looks like the the later batch's from the capacitor vendor where not the same as the samples they gave us for evaluation and used to build your PP1 PCB :(

    BTW I just ordered all the components for the Inverse RIAA network - I need to order "odd" resistors values for a Test jig to be used to 100% IQC the MDAC2 crystals so we dont have a repeat of the Crystal problems with MDAC + the MDAC2 crystals are manufactured by a new vendor I visited during my trip to China last month.
  2. Achim

    Achim pfm Member

    Thanks for your info!
  3. jirij

    jirij Virtual Member

    I guess one upside is that this would allow MCU firmware updates from the microSD card itself, no external computer required, assuming the microSD (or normal SD) slot is easily accessible. :) I'm still watching linux-next commits to see whether I can get i2s slave working on the nanopi m1 - can't bet anything as I won't be going to Munich, but May is a long time away. :)

    Game on!
  4. BigDog

    BigDog pfm Member

    John, can you please clarify whether barrel connector is 2.0mm or 2.1mm?
    Seems like 2.0 is unusual with 2.1 or 2.5 being more common in my admittedly limited experience.

    Considering a custom LPS so like to get handle on a suitable pigtail.

  5. Obi1

    Obi1 Swedish HiFi enthusiast

    Is there any reason for Detox not being ready for production soon?
    It would be great to have something to play with during the wait for the FDAC.
  6. JohnW

    JohnW Trade: Lakewest

    I'm currently spending the first half of my "day" on Detox related production issues - so its very much in the production cycle :)
  7. JohnW

    JohnW Trade: Lakewest

    I guess its 2.1mm although vendors I talk with refer to it as 2mm type - 0.1mm is well within production tolerances :)
  8. BE718

    BE718 pfm Member

    OK, seen enough. You now have another project distracting you. Life is too short, time to move on.

    John, if you be so good as to advise what I have paid in development costs so I can re-sell my slot for the fdac and detox.

    If anyone is interested in my slot please pm me

  9. Ian M

    Ian M pfm Member

    I've been thinking the same way as you but I think eventually I might regret not getting the FDAC, just to see hear what it's like. Since this is not a closed list yet there is not any incentive for anyone to buy your slot at the moment unless you sell it at a discount.

    My problem at the moment is that I no longer have an MDAC and am feeding my current DAC from a Network Audio Adapter - SOtM SMS-200, so I don't know if the Detox is any good to me at the moment.
  10. JohnW

    JohnW Trade: Lakewest


    What makes you say that?

    Detox and MDAC2 are the only projects we are working (asides from the mini-streamer test PCB & our "XMOS" USB development PCB to confirm 769KHZ PCM and DSD512 operation, software, clocks and dual 9038 etc).

    All will become clear at Munich and the reasons I cannot give more details.

    My daily "projects" consist of:-

    Detox production updates currently:-

    1. Crystals samples approval

    2. Approval of a suitable PSU for UK / EU and US

    3. BOM cost reduction and clarifying vendor details

    MDAC2 Project:-

    1. Approving the Crystals for main oscillators

    2. Approving magnetics

    3. Approving connectors

    4. Approving the new Flexible foil to the front panel

    5. Build an incoming IQC test jig to test the Crystals before they are used in production so we dont encounter the same failures as seen on MDAC.

    I just purchased a Agilent Network analyser from the Philippines of all places for the production line in China for this purpose - but refuse to pay US$7000 for the extra crystal test adaptor* so I have to design our own test adaptor..

    * there is a second hand adaptor on Ebay but its still US$3800 + shipping plus Tax and import duty of 25% give or take...


    6. Updating schematic so Jarek can start work on the SOC PCB / test PCB

    FDAC (much the same as MDAC2 as they share many of the same components)

    1. Building an Inverses RIAA for production line testing of the phono stage (parts ordered yesterday)


    1. Confirm DC servo operation range to balance expected DC offset of 6n23 Tube after confirming Spice models of the tubes in hardware over the weekend.

    Please DON'T rush to conclusions - there are commercial reasons I cannot say more about Munich - but Detox and MDAC2 will be available :)

    It upsets me to get such a post as I spend so much of my time currently working on production related issues - I feel relieved once I've cleared the daily Email traffic and questions etc. from Asia and I can finally get back to working on the MDAC2 Design.

    As we know what components are used on MDAC2 I have already started the sourcing / vendor / sample approval...

    Yesterday I placed a large component order for the MDAC2 prototype PCB (also components for the Inverse RIAA EQ & Crystal test jig)

    Oh I forgot to mention not only did I just purchase the Network analyser for the production line at silly money (the crystal adaptor alone would cost used US$3.8K+), but also this week a stereo Microscope for the lab bench as the components on the MDAC2 / FDAC are so tiny - they are really designed for the mobile phone industry so have been shrunk to an almost "human" unusable size... Mosfet packages 0.77mm by 1.7mm (with 3 connection pads to be soldered to the PCB).

    So yes - I'm just alittle pissed with a post like this as I've spent every working moment of the day on these projects and have pumped in FAR more funds than I've received in development funding to make these the greatest designs I can... and ironically I'm working everyday on production related support for these designs!
  11. JohnW

    JohnW Trade: Lakewest


    On a case per case basis (no pun intended) I can loan you a MDAC "shell" for the MDAC2 upgrade if your interested - by Qtys. are limited...

    I hope to be able to source some MDAC "old dog units" from the service department which will make for good donor units (from MDAC2 we now only need the front panel + Sleeve).
  12. Ian M

    Ian M pfm Member

    Thanks for the offer John but I had no plans to get the MDAC2. I will wait for the FDAC.
  13. BE718

    BE718 pfm Member

    Sorry John, but I am not sure how to interpret your comment

    "Detox and an undisclosed project - which will be revealed at Munich."

    Detox, MDAC2 and FDAC are disclosed projects, unless you are implying the FDAC is morphing into something else - commercial partner?

    So another 6 months until detox and mdac2 are available. How many times have we been told this before?

    Even then the FDAC still wont be available.

    So I have to say, respectfully, that however hard you may be working or aggrieved you may feel that the project is questioned, it is still a distant and uncertain outcome for the rest of us.

    Now some may want to continue along for the ride but my decision currently, unless some compelling information convinces me otherwise, is to seek someone to take over my slot.

    My best wishes for the project.
  14. Clerenlas

    Clerenlas Well-Known Member

    Thanks, John. If the FDAC becomes available before 2020, I might well be interested in the 50% offer. 🙂
  15. Steven Toy

    Steven Toy L3 Toy

    This seems like an option I should wish to pursue. I would have a buyer for the MDAC(2) if it was just the cost of an additional board.

    This project had dragged on for longer than is reasonably necessary, IMO but I am not giving up on it yet.
  16. BigDog

    BigDog pfm Member

    Thank you for clarification, John. You likely correct on the tolerance.

    Sorry to distract but is the 10mm barrel also important?
  17. JohnW

    JohnW Trade: Lakewest

    I just checked the connector vendor catalogue and they do have both 2mm and 2.1mm types listed in there Table although they have no 2.1mm connectors!

    The 9V DC in connector on the Detox PCB is 2mm, although I'm 99% certain a 2.1mm will be OK as the ground connection is a "sprung" contact that applies pressure on the centre pin so 0.1mm will be OK.

    But you really don't need to worry as our Detox PSU vendor contacted me earlier today to confirm I wanted samples of the US 110V version - I already wired funds for them last week so you will have a 110V PSU with your Detox.

    The PSU is rated at 9V DC at 1300mA so it can provide significant power for "self powered" DAC's. The Detox's USB1.1 isolated supply is about 80% efficient so we need some extra current headroom - I'm trying to meet a 500mA Max on the USB1.1 output.

    The USB 2.0 output is good for atleast 500mA, on the MDAC2 / FDAC the USB section is internally powered via an isolated supply (via a tiny transformer) anyway to reduce any negative influence of externally noisy USB computer power.
  18. JTC

    JTC Saint Alphonso!

    Hi John, I've decided not to have my MDAC L2 recapped and wait for the MDAC2 board. I am not certain where I am with R&D payments, etc. - I do know I *was* up-to-date as of the last call, and you were doing something for me re: the phono stage I loaned you - but to be honest I am lost. How do I go about switching to MDAC2 and transferring my dev funds?
  19. BigDog

    BigDog pfm Member

    Thanks for the connector info which will be important if I DIY an LRPS...even if not for use with the DETOX.
    Also appreciate knowing a 110V PSU will be supplied and will meet the JW Seal of Approval.

    I will only be using the USB2.0 output of the DETOX. Hopefully some consideration was given to the inputs of my non-JW-DAC and the DETOX design mitigates some of those potential issues in my setup.
  20. Sibbers

    Sibbers pfm Member

    Is this accurate? What's the reasonable expectation for FDAC?

    I only ask because I'm beginning to feel a bit hoodwinked when I bought into the concept of building a no compromise DAC without a program manager to distract and force compromises (MDAC2). On reflection, you must have realised you weren't able to deliver within the expected time frames and could have done a lot more to satisfy the people that helped you to get your dream off the ground.

    I'm up for the concept, I just wish the dates were a little less "soon", "6 months", "I have another project that'll *speed things up*", and then I would just enjoy the journey, but when I keep thinking we are nearly there and we're not then I start to wonder if my part in this gig is actually a bit less appreciated than I thought. Happy for it to happen a few times, but it's become the most predictable thing about this pursuit.

    I don't intend to cause offence, I'm on board with the dream - more so than the end product tbh - I just would prefer that reasonable questions were answered sincerely and not left unacknowledged. If it's next Christmas or even the one after that, at least I can go buy a DAC for the mean time...
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