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MDAC First Listen (part 00111001)

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

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  1. timola

    timola pfm Member


    Ingenious solution to the oven problem....let's hope it works.
  2. canofan

    canofan pfm Member

    Please see to it that the flow of air inside the oven is evenly spread. and that before any modifications. I had such a problem with the heat spread.You might need well positioned deflectors, otherwise you risk overheating the components by slowing the airflow.
  3. ti33er

    ti33er pfm Member

    Thanks John

    I guess there are almost always teething problems with new equipment ...if it's not fit for purpose in the end, can you still return it? 8-/

  4. JohnW

    JohnW pfm member

    https://www.dropbox.com/s/uaps7xb7fnjadyw/First SMD board.JPG?dl=0

    The first PCB from our mini SMT line :)

    The oven is really bad I had to hand reflow some parts after the process - its a very fine balance between reflowing and damaging the board.

    Better reflow ovens are not that expensive (around 5K) so I'll will buy one as soon as funds allow, it will be certainly required for the Detox and MDAC2 PCB's - we can struggle with the current oven for the Streamer / DevDAC boards to generate the funds.

    Guys (any any Ladys?) we are really getting closer - I can see the light at the end of the tunnel :)

    Its still not hit me that we can now manufacture units in-house!
  5. JohnW

    JohnW pfm member

    I hate to use such terms as POS, but the oven really is not fit for its purpose - it was only GBP700 or some such, so I got what I paid for!

    I'm just SOOOO glad I decided to spend the extra funds on a decent PnP machine - it basically worked flawlessly (ignoring my own programming errors)!
  6. JohnW

    JohnW pfm member

    The trouble with the Oven is that it lacks thermal power for its own internal volume - to get it even remotely to function you have to run the heaters at 100% duty cycle and program the oven to follow its own heat-up "thermal profile", but doing this means the ovens controller is basically operating open loop - there is no control.

    With no real thermal control your at the mercy of the ovens starting temperature and the thermal mass of the PCB etc.

    I got what I paid for - still I can say I learnt alot about relowing profiles, being thrown into the deepend is not recommended but can sometimes be effective...
  7. JohnW

    JohnW pfm member

    Yes, the board will have USB, Coax and optical input + the streamer "inputs".

    Bare in mind these PCB's should be housed into a suitable enclosure to prevent damaged from Static, dust and dropping conductive objects onto the PCB.

    For sure the FDAC will feature a different streamer PCB - the current PCB is designed around the physical constraints of the MDAC chassis.
  8. JohnW

    JohnW pfm member

    Yes MDAC2's can function as Master / Slave mode with Volume level communicated between the Master / Slave.
  9. JohnW

    JohnW pfm member

    MicroSD cards are a total pain and unreliable - they are in fact the RPi greatest cause of product returns - I understand that the eMMC interface is VERY fast - Bootup is very noticeable faster with eMMC.

    1. The CM3 module with onboard 4GB memory is nearly impossible to source - the CM3 Lite does not seems as to be as popular with Farnell has about 5K instock, and the 4GB CM3 on permanent back order. I ordered 4 modules earlier this year and they still have not arrived.

    2. The eMMC memory interface is not shared with the USB BUS, this allows us to offer 384KHz simultaneous Record and Playback directly to eMMC - this BW is at the very limits of the CM3 USB BUS BW, forget also trying to stream the Data over the network (the Ethernet / WiFi is interfaced to the USB BUS).

    3. The Raw cost of the 64GB eMMC memory IC is US$28 - thats not too bad considering 64GB can hold alot of local Music.

    4. I PERSONALLY want a tiny unit that locally holds my most often listen Music - without messing with thumb drives, or network connections etc.

    For my personal usage, I see the "Streamer" more of a media player - I'm not interested in streaming services... But I'm OK to discover new music via Spotify or Network "radio" stations...
  10. JohnW

    JohnW pfm member

  11. JohnW

    JohnW pfm member

    I just thought I'd share this with you - I might have mentioned that I've had to recently purchase Microscopes for the lab as components have become so small its impossible to work with them using the naked eye...

    This IC on the DevDAC PCB has 16 electrical connections to the PCB and you gauge its size by the tip of the ball point pen next in the lower left hand side of the frame...

    https://www.dropbox.com/s/ohxaqi4g5t0ipnw/Chip size.jpg?dl=0

    It does not help my eyes are getting worst with age - but this is crazy!

    Oh, and you can also see the soldering quality of our little SMD production line :)
  12. paulski

    paulski pfm Member

    John, I’ve emailed you a link to a UK stockist with some 4GB units in stock.
  13. JohnW

    JohnW pfm member

    Hi Paul,

    Thanks for the links, I've been dealing directly with Farnell's RPi division WRT the CM3 module - partially because they are manufactured 5 minutes away from IAG SZ R&D centre.

    Earlier in the year I tried to make contact with RS components RPi division but with no luck - but it looks like Farnell are useless so I need to work harder on RS. I also have the difficulty that RS will not ship to me in the Czech Rep. for a specific reason, but we can work around this if need be.

    The standard CM3 (with onboard 4GB is OK for those who dont want local storage - while the CM3 Lite is needed for units with larger memory installed.
  14. Rune

    Rune pfm Member

    4GB is on the low side so 64GB eMMC memory + CM3 Lite really is the better solution.
  15. JohnW

    JohnW pfm member

    Yes, basically most of the 4GB is used for the software + backup images, we can even try 128GB later but the IC's are almost US$60 each... the sweatspot seems to be the 64GB pricing.
  16. sq225917

    sq225917 situation engineer

    Soldering looks good on those little fellas John.
  17. iansr

    iansr pfm Member

    Happy to onward ship from RS in the UK if that helps.
  18. JohnW

    JohnW pfm member


    Thank you - I'll keep that in mind.
  19. JohnW

    JohnW pfm member

    Here's the fully built DevDac Revision A01 - without RCA Audio output connections or SPDIF input board fitted:-

    https://www.dropbox.com/s/ajdj72ygooqny81/DevDAC A01a Built.jpg?dl=0

    The Devdac was designed as a simple DAC for testing / development of the Streamer software / system. The customised version for PFM will be modified with improved clock circuit and the high quality RCA's as used on the MDAC.

    As it is, its a step sonic improvement over the MDAC in most areas - afforded by the dual ESS9038Q2Ms...

    DSD is very impressive, and we will provide a DSD sample file on the streamer local storage when shipped.
  20. ti33er

    ti33er pfm Member

    It's a bigger board than I thought it would be!

    Are those WIMA parts (red caps)?

    Nice to see some hardware again - does this actually work i.e. You've pumped some tunes through it? :)

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