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MDAC First Listen (part 00101100)

Discussion in 'audio' started by timola, Nov 25, 2015.

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  1. timola

    timola pfm Member

    Hi John,

    I've just been listening to vinyl at a friends house and it's sheer 'liquidity' 'smoothness' and 'richness' right across the frequency range is awesome compared with digital.....I was wondering how good the jitter will be on the FDAC will this have a seriously accurate/high precision clock so that the jitter can be reduced as much as technically possible and be class leading in this regard?

  2. JohnW

    JohnW pfm member

    High quality "vinyl" just sounds correct!!! - the only thing that comes close is "pure" DSD...

    PCM Digital to my ears just sounds like a bad imitation - reproduces sound but not realistic!

    FDAC with DSD will be very close to Vinyl - but I cannot comment on PCM as I've never heard it sound as good.... But who knows whats possible once we are able to try various ideas with the FDAC's FPGA.

    Detox PCB should be here tomorrow....

    These past couple of days I've been struggling with the FDAC Class A output stage PCB layout (redesigning it to use the Chassis Base as the heatsink).... I'll get there I just need to try various layout ideas...
  3. JohnW

    JohnW pfm member

    Sorry for the delay in replying the FDAC PCB is causing me to pull my hair out - the Detox design just flowed so nicely...

    The FDAC Lite will have a HQ internal PSU.
  4. misterdog

    misterdog Not the canine kind

    Yes but to put it into context, £ 2-3 K. for a turntable, £ 1500 for a cartridge which will only last for 2 to 3 years, £ 1500 for a phono stage to boost the output of the the cart, and £ 15/20 for a vinyl album.

    Oops forgot about the the record cleaning machine to remove static and 'stuff'.

    Say £ 150.

    but yes it sounds sublime. :eek:

    Makes the FDAC seem like a bargain. :)
  5. ti33er

    ti33er pfm Member

  6. BE718

    BE718 pfm Member

    Define "correct" :).

    I know you have commented previously about your experience in a studio comparing the live/recorded sound from an instrument with DSD, but have you been able to do the same with a vinyl cut in the same circumstance?

    I'm not sure "sounding like vinyl" is selling the idea to me. :)
  7. JohnW

    JohnW pfm member


    I believe your negativity towards vinyl is directed at its technical imperfections - Yes vinyl measure poorly - but while as an engineer measurements are a "Badge of Honour" my whole reason for basically dedicating my life's work is to the reproduction of Music.

    Its my experience that the only format avaible to the consumer that REALLY sounds realistic (Ignoring the Crackles and Pops!) is high quality vinyl (And possible with PURE DSD).

    As Misterdog has pointed out decent vinyl does not come cheap - a budget Vinyl setup can put one off for life.

    Its my experience that unlike any PCM I've heard DSD is to all extent "Transparent" so if it can digitise the quality of a High quality vinyl system then I'm good with it!

    I DON'T CARE about technical performance if it sounds wrong - at the end of the day only capturing the "Beauty" of Music matters to me - PCM Digital is unable to really sound "Transparent / realistic" to me.

    PLEASE I don't want to start a stupid never ending circular argument about how "prefect" Digital is! Its REALLY NOT in my interest to pan Digital - however I hope that with the FDAC's FPGA platform we can try some ideas that I believe should help close the gap between PCM & DSD.

    The reason the FDAC has the ADC option is so that we can "Master" known source material.
  8. BE718

    BE718 pfm Member

    I wasnt actually trying to be negative in my comments above, I just asked what your definition of "correct" was and what your experience was of doing direct comparisons to live as you have done with digital.

    However, as you have "pushed" the subject, yes I do also find all the technical imperfections that manifest as things like general distortion, end of side distortion, noise, clicks, pick up (feedback) from speakers, speed/pitch instability etc etc etc quite unbearable. That's got nothing whatsoever to do with my opinions regarding measurement or technical performance, that's just some of the gross and very obviously AUDIBLE limitations of the format.

    I really just dont like the sound, and personally I dont find it realistic (yes I do go to listen to live music of all sorts classical/jazz) quite regularly.

    The fact that a 12" 45 rpm of the same tracks invariably sounds quite different (ie much better) than 33 rpm LP also tells me that the lower speed is fundamentally limited, regardless of the quality of the setup (yes I have heard high end turntables).

    Tell me, how does digitally recorded vinyl sound to you?

    But hey, I have no criticism of what sound people like.
  9. iansr

    iansr pfm Member

  10. iansr

    iansr pfm Member

    As far as you know, is what you ultimately intend to do as regards the extent of the FPGA processing something that has been done before by others? (I think I've read reports of some DACs out there that don't use a DAC chip at all, but I can't remember which ones.)
  11. JohnW

    JohnW pfm member

    Its would be a fool who would claim to be the "first" :) but as far as I'm aware nobody has worked on some the plans I have for the FPGA :)

    Obviously we will also implement some the more standard ideas, but that's not what interests me most the most :)
  12. Rune

    Rune pfm Member

    It might be Rob Watts Chord Hugo you read about.
  13. JohnW

    JohnW pfm member

    Detox PCB arrived today :) I'll post some Pics as soon as my iPhones charged :)

    Te Gold Plated boards look very good - I really must use the same method of screening / isolation for the FDAC Lite / FDAC designs :) Just not sure how to for the larger FDAC Chassis... (maybe smaller individual non integral enclosures).

    The screening can be integral with the smaller FDAC Lite which will share the same Chassis concept as the Detox.

    I need to crack the section on the FDAC Analogue PCB design that's been causing me such a headache these past few days before I can start building / testing the Detox PCB...
  14. JohnW

    JohnW pfm member

  15. fusion5

    fusion5 on the dark side of hifi...

    Looks great :)
  16. Stunsworth

    Stunsworth pfm Member

  17. GWM

    GWM Lost in the 70's

    Pretty impressive board
  18. sam_cat

    sam_cat C'est Crounchifique!

  19. JohnW

    JohnW pfm member

    PCB underside - again you can see the Gold plated sections that are the low resistance Ground conduction paths to the milled chassis internal isolation / screening "walls". Detox PCB A01 underside.jpg

    I'm going to have to installed the compressed airline system in the lab when it comes to servicing these units to ease the pain of having to undo all the screws...
  20. mattgbell

    mattgbell Help the elderly and unwell!

    A work of art, John!
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