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Avondale NCC300 Monos Underway

Discussion in 'd.i.y.' started by Mike Hanson, Jul 5, 2021.

  1. Mike Hanson

    Mike Hanson Lovely!

    After fumbling through various builds, and learning lots along the way, I finally decided to assemble my NCC300 monos.

    The NCC300s are on "T" heat spreaders, designed to clamp on the side of the case. Many others are putting these into repurposed Naim NAP135 and NAP180 cases, with a square tube vented by a fan. Instead, I'm using a Modushop Dissipante 2U with the big heatsinks on the sides. I've never tapped holes before, so that was an interesting learning experience. I had a bit of discarded aluminum, so I was able to practice on that first.

    [​IMG]

    Today I drilled and punched the holes in the rear panel, and installed the connectors. I really like Neutrik for their quality and ease of use, so I'm using PowerCON for the mains, SpeakON for the output, and the corresponding RCA connector for the input.

    I prefer using the knockout punch, rather than trying to drill a clean hole that big. The hole is remarkably precise, and it lets me mount the connectors inside, using the little Neutrik clips with some M3 screws. The resulting appearance is very tidy.

    I also added a set of binding posts, in case the speaker cables aren't terminated with SpeakONs. I believe these are from Keystone.

    [​IMG]

    [​IMG]

    I'll probably drill the holes for the switches in the front panels tomorrow. I'll post more pictures as I progress.
     
    Last edited: Jul 5, 2021
    Tarzan, torstoi, rontoolsie and 8 others like this.
  2. Mynamemynaim

    Mynamemynaim 38yrs a Naim owner

    The build looks great so far .. well done!

    Did Les just supply the boards ? Didn't think he was doing that? Or have you had them a long time...when he did send a few out?
     
  3. Mike Hanson

    Mike Hanson Lovely!

    I've had them for a LONG time, and Les provided them fully populated and tested. I had many other builds in the queue, and I kept encountering challenges with them that made me stay "humble". I didn't want to start the NCC300 project until I felt fairly capable. ;)
     
    torstoi and Mynamemynaim like this.
  4. bugbear

    bugbear pfm Member

    That was certainly Les' intention, and Avondale themselves have supplied many such conversions, but in the NCC300 DIY mega-thread, I think Naim cases were a tiny minority.

    https://pinkfishmedia.net/forum/threads/avondale-ncc300-amp-project.212730/

    BugBear
     
  5. Mike Hanson

    Mike Hanson Lovely!

    Yeah, I've seen a bunch like that from Avondale, but I also know of two others who were repurposing NAP135s in a similar fashion. Obviously, I have no idea of the total landscape of topologies. :)
     
    Last edited: Jul 6, 2021
  6. bugbear

    bugbear pfm Member

    AFAIK (happy to be corrected) there were a limited number of boards and built-boards from Les early on, but then it's been Avondale reworked Naim boxes all the way.

    I don't think there is a DIY NCC300 route available at the moment, wether as Naim "drop ins" or full DIY builds.

    BugBear
     
  7. Mike Hanson

    Mike Hanson Lovely!

    I think you're right. I'm lucky to have this pair here, and another coming from a friend who never got around to assembling his set.
     
  8. Marra

    Marra pfm Member

    Lucky you.
     
  9. Chops54

    Chops54 pfm Member

    Mike, I see two output inductors. I linked out the one on the LS protection board when I built mine.
     
    337alant likes this.
  10. Mike Hanson

    Mike Hanson Lovely!

    Do you mean the ones in the Zobel networks? Les provided this combo as you see it, and he continues to assemble amps with both. I also know that he's put a great thought into these networks, so I'm inclined to leave well enough alone. ;)

    From the Avondale Facebook Group: https://www.facebook.com/avondaleaudio/posts/3463697193650827
     
  11. Chops54

    Chops54 pfm Member

    I do find that odd Mike. When I bought my ncc300 boards from Les and he offered me his LS protection boards he told me to put a link in place of the inductor as only one was needed. I was under the impression that the LS protection board was made originally for the NAP250 hence the zobel network. Maybe I need to give Les a call.
     
  12. Mike Hanson

    Mike Hanson Lovely!

    Yeah, it does seem a bit strange, but Les' Facebook post seems to clarify it:

    IOW, it seems to be a work in progress, with his earlier understanding (perhaps when he spoke with you) evolving to the situation above, with the configuration that I have.
     
  13. Chops54

    Chops54 pfm Member

    The only conclusion I can make is that Les went with the two zobel network later on.
    I don’t do Facebook so unfortunately I haven’t been able to keep up with developments since Les left the forum.
     
  14. Mike Hanson

    Mike Hanson Lovely!

    Yeah, it would seem so.

    I'm not a massive fan of FB, but there are some things that are only available there, so I take the bad with the good.
     
  15. chiily

    chiily PFM Special Builder

    Mike, you really need to build a Krell KSA50/100 clone :)

    Lovely build so far though...
     
  16. Mike Hanson

    Mike Hanson Lovely!

    :D. Perhaps I will one day. I've heard a Krell amp only once, and I don't know what model it was. I faintly recall it sounding very powerful, but dry to the point of seeming sterile.
     
  17. chiily

    chiily PFM Special Builder

    I have some spare PCBs from the original diyaudio buy if you are are interested.

    I wouldn't call my KSA50 sterile :)
     
  18. Mike Hanson

    Mike Hanson Lovely!

    It was a long time, and only a single audition. Additionally, I was probably biased against it at the time, as Naim was the standard bearer of "British HiFi", while Krell (and Mark Levinson) represented "Team America". ;)

    I'm currently overflowing with amp builds. Once I get through them, I may take you up on your offer of the Krell clone boards.
     
  19. Mynamemynaim

    Mynamemynaim 38yrs a Naim owner

    Hi mike
    Good to see your 300 build going well
    I've just started a similar project myself...but am still at the "asking dumb questions" stage
    Here is a picture of my proposed layout (of one mono)

    though this is not finalised (brown paper is outline of Modushop case size I'll be using)

    Waiting on parts to arrive before more progress can be made

    [​IMG][/url]Ncc300 by rock solid, on Flickr
     
  20. 337alant

    337alant Negatively Biased

    Why do you plan to use a VBE ?, the NCC-300 already has built in front end regulation
    Alan
     
    Mike Hanson likes this.

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