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MDAC First Listen (part 00101000)

Discussion in 'audio' started by fusion5, Jul 26, 2015.

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  1. fusion5

    fusion5 on the dark side of hifi...

    With two MDAC2 you would configure one unit with a highpass filter and the other one with a matching lowpass filter for your sub amp.

    Since John brought up the idea of combining MDAC2 with MDAC slaves. Maybe it's possible to use one MDAC2 for your main speakers and an old MDAC for your sub. In this case the MDAC2 dsp would have to process both filters.
  2. fusion5

    fusion5 on the dark side of hifi...

    Sounds intriguing. I think I would go for the XSQ variant. Are there any use cases which would benefit from the higher dynamic range?
  3. jirij

    jirij Virtual Member

    PCM in the form of wav/flac can store up to 8 channels and the MDAC2 can present itself to the OS as a 8-channel playback system via USB. It's then up to the software to either play the file as-is (which works if you have ie. 7.1 speakers set up correctly and the file is 7.1) or somehow mix the channels (ie. 7.1 to a 5.1 setup or vice versa).
  4. JohnW

    JohnW pfm member

    Well it will be a "Battle" between the subjectivist's who 'only' listen and Technocrats who only go by measurements :) - I suspect I'll be going for the XSQ version - IF it performs as I expect...

    It will be interesting as the ONLY difference would be the use of Transistors or MOSFETs in the input differential stage.
  5. JohnW

    JohnW pfm member

    Yes, the MDAC2 via the extra 'Slave' units can either be configured as:-

    1. Multi-channel via the USB or our proposed Oppo Blueray/DVD player extraction card. So 2 MDAC2's would give you 4 channels, or 3 MDAC2's wil give you 6 channels etc..

    2. "Stereo" but each MDAC2 would be configure with different filters for Active speakers setups. One unit configured with a Highpass filter and the other one with a matching lowpass filter for the Bass / Sub Woofer. The Crossover software provided by MiniDSP framework if all goes well during my pending trip to HK :)

    'Slave' MDAC2's are in fact standard MDAC2's, but can be hidden away as they will be operated via the 'Master' MDAC2.

    MDAC2 'slaves' are offered at a discounted development cost when combined with a Master MDAC2 (as you have already helped finance the MDAC2's development with the first MDAC2 'Master' unit development payments).
  6. JohnW

    JohnW pfm member

    We plan to offer an Oppo upgrade service where we will fit a Multichannel digital extraction card allowing a bit accurate multichannel feed to the MDAC2 + Slave units :) This also access the "Bit Perfect" DSD stream for SACD playback via the MDAC2 :)

    You can also reply Mutli Channel decoded PCM audio via the USB (So the PC performs the DTS / Dolby decoding).
  7. JohnW

    JohnW pfm member

    Sadly the time is approaching where I'll have to close the MDAC2 / MDAC2 Slave order books as I need to arrange production with a firm number of units - recently I've had a few requests, so if anyone's undecided it will be your last opportunity to join our project :(

    You can be sure as we approach the Christmas delivery time and the first units start to ship we will be inundated with requests here on PFM, but what to do...

    I also believe there is a good chance that the full width chassis will be ready to ship with the first units, allowing us to ship complete & tested units (so no need to DIY upgrade your original MDAC if you decide to go for the full width chassis).
  8. fusion5

    fusion5 on the dark side of hifi...

    How many orders for regular units / slave units do you have?
  9. JohnW

    JohnW pfm member

    With the Toy / Fusion "At Cost units" A little under 200, so we will round up and add a few extra in case of shipping damage and losses etc, due to the fixed production number it would be otherwise impossible to replace missing units.
  10. scubaboy

    scubaboy pfm Member

    Hi John, PM sent.
  11. Hi John,

    I'd be interested to learn what devices you are using for the MOSFET version? Low power P-channel devices can be hard to find...

    Cheers, Jack.
  12. EIffel

    EIffel Cereal Killer

    ... tough choices! ;-)

    I'd certainly be interested in a full width chassis with my at-cost unit. This will then leave me with a redundant MDAC L3/Fusion and a defective standard MDAC (which may be repairable), in storage with you.

    Would these units be able to work as slaves to the MDAC2 for, say multichannel applications?
  13. ChrisPa

    ChrisPa pfm Member

    My understanding is that the slaves are mdac2s,
    Unless it may be possible to have spdif outputs from the master mdac2, in which case an original mdac could potentially be used
  14. Steven Toy

    Steven Toy L3 Toy


    Including slot-loading CD drive?
  15. dtd

    dtd pfm Member

    Full width chassis, please!

    Will the full chassis include a HQ PSU or something standard?
  16. paulski

    paulski pfm Member

    So if I go straight to full width case MDAC2 then my donor unit is effectively redundant? Also, what's the likely additional cost of the full width case option and will that depend on if you're part of the VFET project?
  17. JohnW

    JohnW pfm member

    Thank you and welcome to the MDAC2 project :)
  18. JohnW

    JohnW pfm member


    Something like cost + GBP100 development to cover design of the front panel, software & the HQ PSU.

    A good guesstimate would be GBP350.... (without the CD slot loader).
  19. jirij

    jirij Virtual Member

    Theoretically, the "master" could be completely standalone and using standard means of signal redistribution, ie. via SPDIF (coax or optical) lines to slaves + a shared clock bus (again, ie. optical line with external splitters), applying whatever filters necessary itself. The slaves could then be anything - MDAC2, MDAC1 (can it receive clock?), or any other clock-lockable DAC. Theoretically one could use the output without locking onto the clock (if the slave DAC of choice doesn't support it), but that could put things out of phase.

    However this design could suffer - not enough DSP power, not enough digital outputs, etc. -- we'll have to see what John comes up with. :)
  20. JohnW

    JohnW pfm member

    The slot loader will be an optional extra.
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