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MDAC First Listen (part 00111011)

Discussion in 'audio' started by fred sonnen, Mar 11, 2019.

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  1. fred sonnen

    fred sonnen pfm Member

    Thanks for the lineup!
    It would be nice to have a time table, too. Maybe it's easier for you to give us one with dates relative to each other than a fixed one.

    "Internal Rubidium Atomic Clock": Could you say something about this solution and the differences / added value to "MDAC2 Advanced Clock Option 2"

    Since I asked for everyone and to get a decision basis, here is my desired config:
    • FDAC (including option "MDAC2 Advanced Clock Option 2" and "MDAC2 Tube") - Full Width case
    • Internal HQ PSU, Buffered / Non Buffered Headphone Output
    • Various modulator options (user swapable) - advanced FPGA versions released over time.
    • HDCD PMD200
    • Vishay Bulk foil resistor: Depents on the costs: I suspect there will be several stages of this development.
    Does it make sense / is it a simplification for you if we put together a spreadsheet with the desired configs?
  2. JohnW

    JohnW pfm member


    All MDAC2 options will be available upon initial release (same PCB design) - different component build levels.

    The "Internal Rubidium Atomic Clock" is the highest clock performance version of FDAC - the Rubidium clock replaces the Advanced Clock option 2 Oven temperature controlled Oscillator - however long term drift of both versions is automatically corrected, so the need for a Rubidium clock is questionable - but ultimate clock performance is a good place to be...
  3. fred sonnen

    fred sonnen pfm Member

    Thank you. That was to be expected as you wrote: everything is on one PCB ;-)
    Whats about the FDAC Options:
    • Ad ons
    • Full Width case
    • FDAC front panel
    • ect.
  4. JohnW

    JohnW pfm member


    I'm making no plans for FDAC until the MDAC2 has been delivered... Only that I'm designing-in an upgrade path with the MDAC2 Advanced option 2 / Tube PCB to FDAC chassis.
    Morph3R, ti33er and Rune like this.
  5. Bob L

    Bob L pfm Member

    John, in your answer to Fred, part copied below, is Option 2, "Advanced Clock Option 1", the same thing as the "MDAC2 Streamer" option shown on the Lakewest website?


    "In Answer to some of your Questions:-

    1. MDAC2 Basic - no streamer function, Basic referenced Clock (does not support external Clock locking I/O, or external I2S for ADC / DSP / Master slave operation), ASRC operation with SPDIF inputs.

    2. MDAC2 Advanced Clock Option 1, Adds TCXO referenced Clock enabling the external Clock I/O and I2S ports, Internal Detox modes and also adds Streamer with internal M.3 SSD option, ASRC Free (Bit Accurate) SPDIF operation....."
  6. JohnW

    JohnW pfm member

    Hi Bob,

    The two Advanced Clock options related to the MDAC2 Clock circuits - however the media player (Streamer) option is required for its CPU power to control these options irrespective if you intend to you the streamer or not.

    The "Streamer" hardware allows local playback of files (from internal SSD drive installed within the MDAC2 Chassis) - so you don't require an internet connection to actually use the "Streamer" - really I should refer to it as a Media player.

    You can Bit accurately copy (rip) your CD's onto the MDAC2's internal SSD drive (if installed) and then not need to touch the CD's again while using the MDAC2.

    The Advanced clock option II has quite heavy CPU requirements - it can graphically display the clock error / drift to sub Parts per Billion (PPB). On the current lab prototype circuits I see clock error of typically less then 0.5 PPB. Production boards will have a custom temperature controlled oscillator to reduce this error still further.

    I'm waiting upon the custom temperature controlled oscillators to arrive - I had to order 100pcs MOQ which just adds to the upfront costs... But I'm pleased with the way the design has come together (all the circuit blocks) - I just hope that the MDAC2 sonically it lives up to the effort and expense.
  7. Bob L

    Bob L pfm Member

    Thanks John- very helpful.
  8. sberry20118

    sberry20118 pfm Member

    Hi @JohnW

    Just had a look at the website and don't see what sample rates the network input of the MDAC2 supports (for streamer option)?

    Is PCM384 and DSD256 supported on ethernet input?

    I've got your fantastic Pro-Ject S2 DAC (great review and superb measurements in the newest Stereophile mag by the way).

    I use the Pro-Ject S2 DAC with HQPlayer to up-sample to DSD512, so I've been patiently waiting for one of your DACs to support DSD512 on ethernet input.

    I've been hoping the MDAC2 is 'the one'! I know from experience the RPi's struggle with >PCM192kHz but don't know much about the CM3 board. Maybe it's better than the RPi3 in this regard?

    eevo1969 likes this.
  9. alloja

    alloja Well-Known Member

    Hi John,

    In the same vein, but at the other end of the scale, could you please also tell which of your planned designs will be able to play files sampled at 32 kHz?

    sberry20118 likes this.
  10. JohnW

    JohnW pfm member

    We guarantee PCM 192/DSD64 however PCM384 and DSD256 work well in the lab.

    DTS has worked with HQPlayer upsampling to DSD512 but I understand there are a few dropouts - maybe DTS will post here directly.
    sberry20118 likes this.
  11. JohnW

    JohnW pfm member

    44.1KHz / 48KHz based sampling rates without ASRC (over USB) - any other "odd" frequency require the ASRC mode, but I suggest that for 32KHz your not going to notice any sonic degradation.

    The clock architecture of the advanced clock option 1 & 2 would allow non ASRC mode with extra software development... but I question if the extra development effort its really justified for 32KHz....
    sberry20118 likes this.
  12. sberry20118

    sberry20118 pfm Member

    Oh wow, that's fantastic to have DSD256 working on ethernet input, in the lab.

    DSD512 over ethernet input would be amazing one day, but DSD256 is enough for me.

    What's the technical reason/s you can't guarantee PCM384/DSD256 on ethernet input, if it's working well in the lab?

    Only if you don't mind me asking of course.
  13. Spike

    Spike pfm Member

    Serious question, what happens if I die before this project is completed, will I get my money back?
    HarryB likes this.
  14. Rune

    Rune pfm Member

    Native DSD512 works with the MiniStreamer. So it should also work with the streamer in the MDAC2.
    sberry20118 and JohnW like this.
  15. JohnW

    JohnW pfm member

    We cannot take into consideration Network traffic of ones setup... higher data rate increases the load on the network... I'm just trying to avoid troublesome owners who are waiting in glee to "troll" about issues when in fact related to there own local network limitations.

    95% of PFM sponsors are decent people. but a few are aggressive and seem to be out to cause trouble... Network issues are a perfect opportunity to fill the forum with negative posts which are beyond my control...

    I don't have anything special in the lab WRT to our local network - but during testing, DSD256 (native) is streamed without troubles... I hope it proves to be the case in the wild outside of the lab... :)
    sberry20118 likes this.
  16. JohnW

    JohnW pfm member

    Any funds forward are ONLY for development sponsorship - and reserving a production position for a MDAC2/FDAC "At Cost" - for the options sponsored.
  17. Space is the Place

    Space is the Place pfm Member

    Don't worry Spike you'll come back like Patrick Swayze in Ghost and guide me fitting my MDAC2 board, like Patrick guided Demi at her potters wheel...

    Oh, my love, my darling
    I've hungered for your touch
    A long, lonely time
    Time goes by so slowly
    And time can do so much...

    MDAC development cost
    Are you still mine?
    I need your love
    I need your MDAC2 board
    God speed your MDAC2 board to me...
    kennyh, sberry20118, brumjam and 2 others like this.
  18. sberry20118

    sberry20118 pfm Member

    Fantastic, thanks John.

    I initially thought it was perhaps a Pi CM3 board limitation but if not, I’m happy.

    I already have HQP DSD512 working without hiccup (all hardwired ethernet , no WiFi) to my S2 DAC , so should be fine. DSD256 is enough for me though.

    Looking forward to the MDAC2 with streamer option.
  19. sberry20118

    sberry20118 pfm Member


    I know many devices that support DSD512 for ethernet-to-USB conversion but very few that do ethernet-to-I2S-to-analogue at DSD512 (or even DSD256 over ethernet input)

    I think the latter conversion (ethernet-to-I2S-to-analogue) presents a different technical/performance challenge (hardware challenge, not just OS challenge) which is why so few hardware do this at DSD256 or higher?

    @JohnW is far better qualified than me to explain the challenges of DSD512 with ethernet-to-I2S-analogue conversion though (increased phase noise issues ?).
    Last edited: Mar 17, 2019
  20. kennyh

    kennyh pfm Member

    Has to be the comment of the thread:D
    JohnW likes this.
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