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MDAC First Listen (part 00111000)

Discussion in 'audio' started by PhilCTTE, Jun 20, 2017.

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  1. Julf

    Julf Facts are our friends

    How hot is "quite hot"? Are all four in the same enclosure, or separate boxes? Have you checked that there is no oscillation going on?
  2. sq225917

    sq225917 situation engineer

    Ncores get barely warm...
  3. Rune

    Rune pfm Member

    No 2 x nc400 + 2x smps600 in each case. And I would say that they gets just as hot a my old AV receiver.

    What do you mean by oscillation in layman terms.
  4. Julf

    Julf Facts are our friends

    Any ventilation holes in the enclosure?

    The nc400's are somewhat sensitive to how they are wired. Bruno was making an issue about how the speaker output terminals are very close to sensitive feedback loop components, so unless the output leads are properly twisted, there is a risk of the input circuits being affected by the output signal. The result would be a high-frequency signal that would be beyond human hearing range, but would cause the amp to continuously put out a fair bit of power (*probably* harmless to the speaker, but could explain the excess heat). Verifying it does require an oscilloscope, unfortunately.
  5. ddenyer

    ddenyer pfm Member

    Not before the VFETs though....
  6. sam_cat

    sam_cat C'est Crounchifique!

    That matches my experience.. Driving a pair of Ergo IX and touching the case its slightly warmer than the surrounding air, but not overly hot. And thats after playing music for a while at a good volume.
  7. paulski

    paulski pfm Member

    Same setup here, same result.
  8. HarryB

    HarryB pfm Member

    Wow! This is so exciting. All of these brilliant new products in the pipeline.
  9. timola

    timola pfm Member

    I'm just hoping this excellent PFM forum can keep hosting this thread long enough so that all my HiFi kit is eventually from the LakeWest design studio (laboratory).

    I try and donate a bit every year to help out TonyL and co. I'm sure everyone here does too...;)
  10. JohnW

    JohnW pfm member

    We have been busy working away here - the PCB's for the MDAC2 streamer and DEVDAC have arrived:-



    Today we placed orders for the components, we are trying to buy as much as we can on SMT reeled stock so we can load these reels onto the PnP machine when it arrives.

    Unfortunately, this means ordering reels in 2K, 3K or 5K qtys which has a dramatic impact on the invoice amount...
  11. sq225917

    sq225917 situation engineer

    Devdac layout looks very tidy John. What's the output stage, op-amps?
  12. ti33er

    ti33er pfm Member

    Hi John

    I thought you mentioned some were being done by hand, although it's probably a lot of fiddly work that could be negated! :)

    Nice to see some hardware!!! :cool:

    Best regards

  13. Rosewind

    Rosewind Lost in Translation

    Please refresh my memory: what is the order of production when it comes to Detox, Mdac2, Streamer board, Devdac, Vfets, Small amps (referred to within the last few pages)?

    I have Detox + Vfets on order.
  14. JohnW

    JohnW pfm member

    Streamer PCB




    We are just waiting for the last set of parts to arrive for the first 8 streamer PCB's (they are held up in customs).

    By next week we should have the first boards built and a couple of the DEVDAC's.
  15. JohnW

    JohnW pfm member


    We are using the same headphone driver as we used on the Pro-ject DAC but in dual mono mode (one device per channel).

    This and the improved PSU design, and the DEVDAC should sound very good - certainly for the price.
  16. JohnW

    JohnW pfm member

    This boards will still be mounted by hand, but we are ordering as much on reels as we can afford so we can load the reels onto the machine when it arrives.

    (For the hand build boards we can remove components from the reels).
  17. Morph3R

    Morph3R pfm Member

    Hi John, can the DEVDAC be used later on as a standalone DAC (to be used for example as an office DAC?) I was interested in buying Pro-ject DAC but now DEVDAC sounds tempting.

  18. JohnW

    JohnW pfm member

    Jarek plans to design a small XMOS daughter board for the DEVDAC so he can use it as a standalone DAC without the streamer PCB - it will require a little DIY Skill (put into an enclosure and mount the front panel) but no soldering will be required.

    We only ordered 2 DEVDAC PCB this time around as the design is untested - but we have 8 streamer boards.
  19. Rosewind

    Rosewind Lost in Translation

    Thanks John. Keep up the good spirit!
  20. timola

    timola pfm Member

    John....Please add FDAC to this list!....:eek::eek::eek:
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