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MDAC First Listen (part 00100011)

Discussion in 'audio' started by highfi, Nov 3, 2014.

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  1. Rosewind

    Rosewind Lost in Translation

    Custom Vfet Chassis for me too :). I am on the original list.
    I hope I am down for a TDAC too some time in the future.
  2. JohnW

    JohnW pfm member

    Close, the empty chassis weight is 9.2Kg... :)

    Each heatsink (one each side) is milled from a solid Aluminium block 320x90x60.

    I'm not one for massive Krell type lumps with sharp protruding fins, rather something more domestically acceptable - so each chassis is 430mm wide 100mm High 328mm deep, I need the heatsink depth to mount the array of output devices, x24 MOSFEt Dumpers & 4x VFET's per Monoblock + Driver devices etc.

    The massively paralleled output dumpers will allow the VFET Amp to drive nasty speaker loads such as my Martin Logan CLS :)
  3. JohnW

    JohnW pfm member

    Thank you for the update, I'll order one to see what we can do with it :) Maybe we can clocklock them to the MDAC2's MASTER clock giving us a HDMI input on the MDAC2 even if I need to buy and strip these units for there component parts.

    This would sidestep the HDMI licence as the fees have been paid on the donor unit.
  4. JohnW

    JohnW pfm member


    Even if in the unlikely event we stay with the 8200MB's then I can exchange your donor units with my own.

    I have a pallet full of 8200MB's I will need to shift sometime in the future :rolleyes: - my bad! but it has to been done the VFET amps really deserve better as they are to be my Statement Amp design!
  5. JohnW

    JohnW pfm member

    Yes, but nothing that would been a show stopper....

    I also discovered that the 8200MB's transformers are 230V only and a couple of the units are to be shipped to US / Canada so not even the 8200MB's transformer is used, also the Fully Balanced output stage design requires lower transformer voltages.

    Once I've arranged the new chassis and I'm happy with their quality then I'll put the donor 8200MB's on Ebay...
  6. JohnW

    JohnW pfm member

    Reenberg, cjayc, BrainC, Jansen & Wardi23,

    If your serious about joining the VFET amplifier project then I can add you to the list and purchase / allocate the VFET's and output dumper MOSFETs for your units.

    The VFET's amps delivery scheduled is determined by the MDAC2 progress - I'm planning to use the VFET Amps to audition the MDAC2 designs as I need far better power amplifiers (and system) then I currently have in my lab to optimise the MDAC2 design - the MDAC2 / VFET amps will be developed in paralleled and thus optimised together as a package - then all you need to do is add speakers :).

    Just PM and I'll forward a PayPal invoice for the first of two installments (the final installment will be requested once I actually start to build the units).
  7. EIffel

    EIffel Cereal Killer

    Custom Vfet Chassis for me too, and I wish to remain on the TDAC list.

    Hoping the MDAC2 analogue board design completion goes well!
  8. JohnW

    JohnW pfm member

    Just one negative about the Milled Aluminium Chassis is that each Monoblock will weigh in at about 20Kg due to the solid chassis and massive PSU - I'm thinking about the cost of shipping... Thats 40Kg a pair!...
  9. ilmostro749

    ilmostro749 pfm Member

    the good news is the PCB of this is about 4cm x 5cm!

    The only bad point, it looks like you need to connect a 192KHz HDMI sink device to the output to get the unit to work. However that might be possible to circumvent perhaps.
  10. JohnW

    JohnW pfm member

    Have no fear, the VFET AMPs will use Vishay Bulk foil resistors by default, impossible not to - these are Statement designs! :)
  11. JohnW

    JohnW pfm member

    Please forgive my ignorance - (I'd still a happy bunny with a CD player and PC / USB streaming) - what is meant by "you need to connect a 192KHz HDMI sink device" :confused:
  12. avole

    avole The wise never post on Internet forums

    Wouldn't it be a good idea to change the title of this thread? It no longer has anything to do with first listens. Any prospective buyer is going to be swamped if they search by a multitude of same-name topics that doesn't help them in their quest for reviews, opinions etc.

    "MDAC Questions and Support" would seem a more logical name.
  13. misterdog

    misterdog Not the canine kind

    Delivery by pallet would probably be a cheaper alternative. As used in industry, the insurance rates are also much better.

    The shipping companies will supply the pallets :).

    I know someone who could supply flat packed poly lined shipping cases :D
  14. Rosewind

    Rosewind Lost in Translation

    Sounds like I would want to pick it up. That would make for a nice car trip. Hmm.
    gariboldi2012 likes this.
  15. JohnW

    JohnW pfm member

    Luckily, Czech Post is not that bad to the UK even for 20Kgs.
  16. JohnW

    JohnW pfm member

    That would be great, then we can meet and listen - and spend sometime explaining the technology behind the amps etc :)

    I plan to have a sofa bed in the listing room above the lab - so it would be possible to stay here at no extra cost.
  17. fusion5

    fusion5 on the dark side of hifi...

    Let's say you've looped in this device between a blu-ray player and a tv. The player will make a handshake with output device to see which resolutions and audio formats are supported. And even if your concert blu-ray comes with a 24Bit 192kHz stereo track, it will get downsampled if the output devices only supports 48kHz.
  18. ilmostro749

    ilmostro749 pfm Member

    Ok - I measured the metal case as 6cm x 7cm x 2cm
  19. ilmostro749

    ilmostro749 pfm Member

    Sink devices are the endpoints in the HDMI chain, Sources and Repeaters are the others.

    Some of these splitters do not need a TV on the end to work, they tell the BluRay player that it supports whatever format. One of my many (think this is the 4th one I've bought!) audio extractors does this. I'll play around next week and see if it's possible to get 192KHz with no screen attached. I know one of the others does this, but it only has a TOSLINK, and it's impossible to find a TOSLINK cable that works over 96KHz. Was tempted to get some glass fibre from 10 Gig Switch and make my own (you can buy the Toslink terminators). I wish I had appropriated some fibre when I had the chance 3 years ago! :rolleyes:
  20. Nick1881

    Nick1881 pfm Member

    Hi John,

    I haven't received an email from Renata yet, just want to check I haven't missed it.

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