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MDAC First Listen (part 00100001)

Discussion in 'audio' started by stellablues, Jul 23, 2014.

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  1. russel

    russel ./_dazed_and_confused

    I used american microsemi to source the hard to get
    2SK186,2SK190,2SJ77,2SK214 for an amp project, might be worth trying them if you need some more.
     
  2. TimR

    TimR pfm Member

    Hi Steven, from a purely practical standpoint, something I'd be careful of is to make sure there is some option to backup the data to another hard drive. The last thing you'll want to be doing is re-ripping all your music once the built in hdd/ssd reaches the end of its life and fails. I don't see a mention of it.

    With other streaming solutions where the music is stored on a PC or NAS it's easy to set up a backup schedule or to include disk redundancy.
     
  3. JohnW

    JohnW pfm member

    Russel,

    Thank you for the info - the Sony VFETs are rather special:-

    http://www.diyaudio.com/forums/pass-labs/248904-sony-vfet-amps.html

    I'm looking forward to completing the MDAC2 so I can get to play with the AMP :)

    I'll be happy once I have the x15 pairs of VFETs in my hands (they are being shipped from Singapore).

    Apparently, originality there where a 1000Pcs, such a shame I came to the party so late - I had the very last pairs for sale!
     
  4. JohnW

    JohnW pfm member

    Michael,

    Once I have the VFETs safely in my hands then I'd be happy to add you to the project - I'll PM you with the cost :)
     
  5. ddenyer

    ddenyer pfm Member

    Hi John, I'd be interested too (depending upon cost). I could provide 2 8200MBs.

    Cheers, Derek
     
  6. fusion5

    fusion5 on the dark side of hifi...

    Thank you, John! This gives me time to sort out some things first:

    My local hifi guy (he builds amps and active speakers) and I are currently thinking about activating the "The Black Monolithic Beasts". This would require a considerable amount of hardware and time given it's a 3.5 way passive speaker. On the other hand we could get rid of a very complex (70+ parts) passive crossover.

    [​IMG]
     
  7. jirij

    jirij Virtual Member

    This has been fixed some time ago, I've updated the wiki page to reflect that.
     
  8. spiderlane

    spiderlane Member

    Thanks jirij - good to know.

    P.S. The Wiki page was vandalised with spam so I took the liberty of restoring it with what I think was the latest non-spam version of the page.

    Cheers
    Mark
     
  9. Spike

    Spike pfm Member

    Hi John,
    I've sent you a PM. However, if I'm not to late I'd like to join. I would like a silver salvaged MDAC. Do I pay you £300 for the first, second and third instalments, and then you invoice me for the salvaged unit, providing they are still available?
    Cheers
    Graham
     
  10. CrazyindianZA

    CrazyindianZA pfm Member

    Hi John,

    When I first bought my M-Dac, someone on this forum suggested that instead of running it through my Arcam 777/888 via RCA, I should use XLR. I have now ditched the Arcams and have connected the M-Dac directly to 2 x W4S Monoblocks via XLR feeding 2 Gallo Reference 3.5s.

    Makes a massive difference, I am really impressed.

    It also seems that there is a new project happening and I may be too late :(. having read through a few of the many pages, I would be interested in a the M-Dac level 3 as a means of getting the access to the streamer. If the streamer is unlikely to happen then level 2 would be sufficient.

    Let me know if it is still possible to join, if not then best of luck with the project.

    Regards,

    Kevin
     
  11. Akasha

    Akasha pfm Member

    Hi John
    your inbox is full so..
    Is it possible for me to join the VFET amp project, it sounds very interesting.
    I might get hold of some some Vfets myself if needed
    and do you have a price estimate for these amps?
     
  12. jamjar784

    jamjar784 Heavy Up

    Hi John, the questions are flying thick and fast. Maybe you missed my query a few pages back?
    Thanks
     
  13. hluga

    hluga pfm Member

    Hi,

    I've tried to set a new 3.13 (-24) kernel with applynig manually the patch but the usb host part has changed so it doesnt work (mdac didnt show on.alsa mixer) I've also tried to install 3.16RC5 and the bug is always present (i test several mpd settings without success)

    Any ideas ?

    Br/
     
  14. jirij

    jirij Virtual Member

    The patch does not apply on 3.12+ due to the rewrite, this is expected.

    By "mdac didnt show on.alsa mixer" you mean that it didn't show up in /proc/asound/cards? Can you pastebin dmesg output after connecting the MDAC?

    (I presume you're using USB as this would be MDAC-unrelated issue for SPDIF.)
     
  15. stellablues

    stellablues pfm Member

    Please add my name to the list for Vfet amps. I am very interested. I heard the pass version at the newport show. I could also try and find some parts if needed.

    edit: are these the models your working with? http://www.circuitdiy.com/product/2sj28-kf-33-2sk82-ke-33-sony-vfet-for-ta-n88-class-d-amp

    thanks,

    Aaron
    Stellablues

     
  16. JohnW

    JohnW pfm member

    Jamjar :)

    For Toy / Fusion owners:-

    MDAC2 L2 £100 for L2 Development fee + L2 PCB "At Cost", PCB target cost £300 to £350 + Shipping

    MDAC2 L3 £200 for L3 Development fee + L3 PCB "At Cost", PCB target cost £350 to £400 + Shipping

    No idea on the MDAC2 Fusion price yet as I've not had a chance to listen to the design.

    A salvaged unit cost £370 (not £350 as I mentioned earlier, as I forgot to include PayPals fees + shipping).
     
  17. JohnW

    JohnW pfm member

    Aaron, Akasha, Derek

    The 2SK82 & 2SJ28 devices you linked to are from the same vendor I ordered the x15 pairs - I've emailed the vendor requesting how many pairs he still has in stock as after my original x15 pairs order the website was updated to "out of stock" - so I'm not sure of the real situation...

    The amplifiers will be based on "New" 8200MB's, with the chassis, transformer, heatsink, connectors and packaging is used from the 8200MB's everything else is dumped.

    The design uses a miniature dual triode for the frontend, using the TDAC's novel balanced direct coupled Tube Gain stage + with symmetrical VFETS used in pure 5W ClassA operation, and a MOSFET "Current Dumper" - the VFETS are arranged to always control the output signal - with the MOSFET current dumpers just "Boot strap" the load seen by the VFET ClassA stage - the VFETs just happily drive a 5W load + a tiny correction signal all day long (ClassA)...

    The Dumper are NOS vertical Hitachi MOSFETs, again limited stock (I still have same from Pink Triangle days).

    Its a low feedback design (however the Feedforward bridge helps to further improve linearity) rated at about 200W to 250W into 8Ohms - with a THD target at 1W of about 0.0005%

    The Amplifier is very much a background project (while the MDAC2 takes precedents), hopefully the first units will be built around Christmas (This year).

    Payment terms would be 2/3rd's upfront (to secure for the donor 8200MB's, VFET's & Lab construction fund :) ).

    Sadly, these are VERY limited editions hand built REFERENCE designs (Due to the limited supply of VFETs, Vertical MOSFET's and the Miniature Tube) - they should be a stunning example of Current dumping taken to the extreme... I'm sure Peter Walker would frown to see Current Dumping mixed with Tubes, VFET's and MOSFET's :p

    They will set the standard for the Lakewest Mimps / MAMPs...
     
  18. JohnW

    JohnW pfm member

    Graham,

    Thank you for your interest in the MDAC2 project.

    Sorry for the delay in responding, I got engrossed in the design of the MDAC2's Analogue section PSU - thankfully it was a construction weekend... finally!

    Yes, if you pay the first GBP300 installment, then I'll ask Renata to send you a PayPal invoice for the salvaged unit - please indicate in the PayPal payment message wither you want a Silver or Black salvaged unit.
     
  19. JohnW

    JohnW pfm member

    Kevin,

    Forgive me for asking (as Renata's "busy" shopping...), but do you have a Toy / Fusioned unit? if you do then you qualify for an "At Cost" MDAC L1 (You would just need to pay the development difference once they are requested for the other level builds).

    If your not a Toy / Fusion MDAC owner then you can join the MDAC2 project by paying the GBP300 installment. :)
     
  20. JohnW

    JohnW pfm member

    Derek,

    I could deduct the cost of the "Donor" MB's from the project cost if we where to use your units - or you could sell your own units (as I'm sure you will get more for them then I can buy new donor units directly from IAG).
     
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