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MDAC First Listen (part 00111001)

Discussion in 'audio' started by ti33er, Sep 12, 2017.

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  1. misterdog

    misterdog Not the canine kind

    Cool, no Lelon caps. ;)

    Is that from the new p+p machine ?
  2. moosemeat

    moosemeat pfm Member

    Hi John,

    I sent you some relevant RS contacts via email... I wanted to check you have received them?

  3. JohnW

    JohnW pfm member

    Yes - Wimas PP capacitors and MELF Thinfilms etc. its a "proper" DAC design :) but everything becomes relative in comparison to the pending MDAC2 designs :)
    Its a good DAC - certainly should be the most advanced DAC for its price...

    By design its better then our little Project DAC - and many good things are being said about the Pro-ject (it just won the ESIA award).

    I'm just debugging the PCB now - II will need Jarek to write the contorl software once I've confirmed basic hardware functionality - but we should have results by Friday.
  4. JohnW

    JohnW pfm member

    Bruce, thank you so much for the info - sorry, I've avoided checking mail today as I need to stay focused on hardware...
  5. JohnW

    JohnW pfm member

    Well Lelon Organics are used - but I've never seen a failed Organic Cap in the 100'000s we have used todate :)

    Yes first complete board from the PnP machine (it only places the SMD components).

    I'd tried the machine earlier on a small streamer PCB, it was test run so only a few component types placed.... So this is the first "complete" board :)

    I'm so VERY happy with the PnP machine, it really was worth spending the extra on the better machine.

    Today I ordered a smaller Reflow oven which should be large enough for Streamer, DevDAC and Detox - I hope it will be better then the current POS.
  6. moosemeat

    moosemeat pfm Member

    You're welcome John. I hope they help you get the CM3s!

  7. TimR

    TimR pfm Member

    Looks really nice, you must be very proud of that :)
    And this was done using the cheap reflow oven that was causing you problems?

    Dumb question: Why does the oven not melt the plastic components?
  8. killie99

    killie99 pfm Member

    Because it's only the surface mount parts (caps, resistors, IC's etc) which go through reflow. After that you place the through hole parts (connectors etc) and either solder by hand or use a solder wave. However, some plastic parts are spec'd to go through reflow.
  9. TimR

    TimR pfm Member

    Ah! Thank you
  10. JohnW

    JohnW pfm member

    Thank you - I've been really too busy to realise how much we have progressed over these past few weeks - maybe once we have shipped some boards we might have time to sit back and go "Wow, I cannot believe we have this in-house production capability"!

    Its been a real learning curve on so many fronts - even installing the Air-line equipment was all new to me - and I made many mistakes (leaks everywhere - in the end I had to purchase an ultrasonic leak detector, would have been so helpful in finding the leaks in our RangeRover Air suspension)!

    While your installing equipment you know what you want to achieve but dont think about the end result, but once you actually start to use the equipment it becomes a game changer - I'm using the new tools to help build R&D PCB's and its really a game changer...

    Yes, and it was a real mess, I had to use hand hot air to reflow the parts that had not soldered (reflowed) correctly.

    So after our GBP700 odd reflow oven was useless (no surprise), I've just purchased a Euro 170 oven (much smaller, but should be OK for the streamer / DevDAC & Detox PCB's)... a sensible purchase I'm sure!!!! but after some research on the internet and with a few modifications (such as removing flammable masking tape used inside the oven) others are getting good results, so it cannot be any worst then our current oven - can it? - well we will find out soon enough!

    Yep, as has been answered already most through-hole components cannot be reflowed (they melt). While I was experimenting with the ovens profile I throw in an old PCB which had been populated with through hole components - you can see the result :) TH.jpg?dl=0
  11. TimR

    TimR pfm Member

    To be fair to the oven, that's pretty much how most of my soldering jobs end up looking ;)
  12. jadidih101

    jadidih101 pfm Member

    Hi JohnW,

    Quote above is from three weeks ago. Do we have a final figure or at least a realistic estimate yet?

    There is now less than three months to end of the year. Do you still see Detox shipped before end of the year? I am not sure where the enclosure and PS are coming from but surely to get Detox delivered by end of the year, shouldn't these have been ordered by now?

  13. ti33er

    ti33er pfm Member

    Hi John

    Perhaps not for the MDAC2 which is finalized, but maybe for the FDAC Streamer...

    It seems this hardware platform with "latest: AllWinner H6 Quad-core ARM Cortex TM -A53 Processor up to 1.8GHZ" is popping up all over and much more capable than the RASPBERRY

    They (many vendors) run this on ANDROID 6 (or even version 7 now), which could be easier to maintain as they provide regular updates and seems one can customize parts too

    Example of such would be the new ZIDOO H6 Pro which can cost a meagre £66-80 for the full retail device, depending where you get it from

    The hardware is Smartphone/Tablet control capable and even 4K Video reproduction with HDMIv2 ...the ZIDOO X9/X10 model has also an HDMI INPUT for recording (and or PIP) meaning one could rip SACD potentially ?

    Just food for thought :)

  14. JohnW

    JohnW pfm member

    Hi Paul,

    After our experiences with the H3 board - I'm keeping arms length from any AllWinner IC...

    The basic problem with these Asian SOC (Hey even the Broadcomm used on the CM3) is support documentation...

    We will need to move from CM3 at sometime - but at the moment the "solution" works so much better then anything else out there...

    iMX8 looked good - but then Qualcomm have apparently bought them so its over to get ANY documentation in the future!
  15. ti33er

    ti33er pfm Member

    Thanks John

    I did spot on Wikipedia about AllWinner having historical Linux Kernel root access vulnerabilities! ...hope they have cleared that up!!!

    Real pity though as the hardware is terrific


  16. JohnW

    JohnW pfm member

    Update on the Streamer / DevDAC progress. Streamer and DevDAC.JPG?dl=0

    Above is the orignal (and now very hacked) Version A01 MDAC2 Streamer PCB and DevDAC A01 PCB.

    Good and bad news - good news is that the DevDAC works well, with dynamic range of around 125.5dB and THD (compensated) of 0.0002%.

    The DevDAC as original designed as a "simple" development DAC, for PFM we have made a few performance enhancements to the pending A02 board primary related to the clock circuit which will be an advance discrete design and added a 3rd clock frequency for non asynchronous (ASRC) mode operation (for SPDIF inputs).

    We will also use higher quality RCA output connectors (the same type as used on the MDAC audio outputs).

    Bad news is that during testing the DevDAC we found an interface timing issue with the streamer PCB. We could "bodge fix" the issue, but I felt is was better to re-spin the streamer PCB to version A04.

    The painful part is that I'll have to scrap GBP600 worth of bare PCB's that I'd ordered and waiting here to be built, and also the solder paste stencil - but its for the better so that all streamer boards are built to the same spec. and "perfect" :)

    We have already updated the streamer PCB design to A04.

    So we will ship A04 streamer PCB's and A02 DevDAC PCB's to those interested in being part of the streamer Beta testing.

    I hope DevDAC owners will be happy with the audio performance, with the Clock updates its a very decent design....

    Its a decent step-up to the design used on the Pro-Ject DAC, with significantly improved PSU, clock design & true balanced output.

    There will be a front panel option offered for the DevDAC - otherwise its controllable via the streamer App.
  17. JuanV

    JuanV Member

    Hello, how can i order DevDac PCB A02 ? Thank you.
  18. canofan

    canofan pfm Member

    I know correlation from statistics and I am trying to understand how a logical twist (if it is the same) could spontaneously happen in digital audio. Anybody with an explanation. Until I connect a Detox I will not be able to evaluate the effect of "decorrelation" on the sound.
  19. fusion5

    fusion5 on the dark side of hifi...

    Thanks for the update, John!

    Judging from the position of the far side mounting holes it doesn't seem possible to mount the streamer PCB on top of the DevDAC.
  20. JohnW

    JohnW pfm member


    The DevDac is designed to be placed beside the Streamer PCB - only in the MDAC2 is the PCB mounted above the mainboard due to space restriction in the MDAC chassis.

    We had never thought about placing the Streamer above the DevDAC PCB..
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