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NAC Servicing

Discussion in 'd.i.y.' started by Southgate, Apr 19, 2009.

  1. Southgate

    Southgate pfm Member

    Is servicing a NAC 72 something a novice DIYer could do?
    What's required parts wise and rough cost?

    Tried searching, but couldn't find much.
     
  2. sq225917

    sq225917 situation engineer

    If you can solder/desolder and aren't colour blind you can service a 72, which parts do you think might need servicing on it?
     
  3. Southgate

    Southgate pfm Member

    Well i'm hoping to buy one in the next week or so. I was going to wait for a serviced one to come up, but they all seem to be unserviced.

    Trying to factor in cost of general 12 year service into what I pay.

    Im not colour blind and I can solder... so might buy unserviced and try it myself.
    I would be doing whatever Naim would do in there 12 year factory service.
     
  4. binnie

    binnie Binnie

    If you want to do it by yourself, just have a look here (under "the preamp bible"):
    http://www.acoustica.org.uk/

    But if you do not want your 72 to devalue (I mean for a further sell) you may also consider the 321s and 729s cards from Neil here on this forum.
    The acoustica mods are already in.
    You can then buy the components you want and try a lot of alternative caps (in this case welcome to the club :D).
    If you do not want to bother with ordering caps, tranies etc... , I think Neil proposes them already built.
    Another serious and great alternative are the 821s from Les at Avondale.
    You can return them if you are not satisfied ...
    Basically, these are the three possibilities.
    Olivier
     
  5. misterc6

    misterc6 What's he building in there?

    Absolutely! You'll get all kinds of opinions but you've asked for servicing as opposed to upgrading and, in order to maintain the Naim sound, I'd advise just replacing the critical components that deteriorate with time with the best modern equivalents:

    replace all the coupling capacitors, like for like with 10 uf 35v tant beads, Farnell have a good Kemet (Cat # 1650978) they're 92p + VAT each and you'll need 4 for the 321 boards, 4 for the 729 boards plus whatever other boards you have fitted.

    replace all the maroon ROE 47 uf 40V electrolytic capacitors with Nichicon Muse KZ series 47 uf 50V (they must be KZ) which can be found on eBay for around £1 a piece.

    Very easy to do as all the boards unplug and the only skills required are desoldering and soldering. If you can't do it yourself, send me the boards and I'll do it for you.

    malcolm
     
  6. binnie

    binnie Binnie

    Sorry Southgate,

    I was to quick, Misterc6 is right, if you "only" want to service your 72, then look into his post. If you want to modify (upgrade) your 72 then you can have a look at the three possibilities I mentioned.
    Enjoy your 72 :)
    Olivier
     
  7. Southgate

    Southgate pfm Member

    So are most/all the service components contained on the replacement 321 and 729 cards?
     
  8. BobMaximus

    BobMaximus pfm Member

    Not really since these are not original cards that have merely been serviced. They are alternative cards that do not sound the same as the Naim originals.
     
  9. The Captain

    The Captain ~~~~~~~~~~

    If you want to keep the naim sound and service as opposed to 'upgrading' (arguable a word anyway) as close as humanly poss, do exactly as misterc6 suggests: 47uf/50v muse kz's and generic but decent 10uf/35v tants. costwise summat like ~£30.

    be aware though that you will undoubtedly be devaluing it by such a diy service, however well you do it. Although if done well enough i wouldn't neccesarily be too bothered- but most will.
     
  10. Southgate

    Southgate pfm Member

    If these cards were changed for new ones, would there be anything else left to change?
     
  11. The Captain

    The Captain ~~~~~~~~~~

    well yes the 324 cards and phono cards ideally need a tickle too.
     
  12. Southgate

    Southgate pfm Member

    I thought the NJ 321 and 729 cards still keep the 'naim sound'?
    Whereas the Avondale mods tend to alter the naim presentation more?
     
  13. flatpopely

    flatpopely Prog Rock/Moderator

    Correct on both counts.
     
  14. BobMaximus

    BobMaximus pfm Member

    It depends on who you choose to believe. I have learned to believe no one.
     
  15. misterc6

    misterc6 What's he building in there?

    I've got a 72. I don't intend parting with it. The way to retain the Naim sound is simply to replace the components I mentioned. You can do it yourself for less than £30. You could e-mail or phone Naim and ask how much they would charge for the work, just make sure you are sitting down to hear the answer. Maybe have a glass of medicinal brandy (preferably Armagnac) close to hand!

    BTW I'm assuming that you have a HiCap, or a clone as a separate power supply. That's the best upgrade going!

    malcolm
     
  16. BobMaximus

    BobMaximus pfm Member

    I've got some isopropanol. Will that do?
     
  17. misterc6

    misterc6 What's he building in there?

    Please can you send me some - I use it for cleaning. I used to get it from the pharmacist but now he takes one look at me and sends me away :D

    malcolm
     
  18. uncl_nigel

    uncl_nigel pfm Member

    Having purchased both NJ (built by NJ himself) and Avondale boards for my 72 and compared both sets with each other and the Naim originals, I can say they both alter the Naim sound.

    The NJ boards stay nearer the roiginal Naim "olive" sound while taking it patially in the direction of the current black box range, whether that is better depends very much on taste !!!
    I sold my NJ boards and kept the Avondale 821A boards. Personally, I preferred the more natural, open, wide frequency ebb and flow of the Avondale boards.

    Nigel
     
  19. batjodel

    batjodel pfm Member

    When considering the de - value of a DIY service - Class A quote £100 - £139A DIY service is £30. Therefore if you sold the amp on got £100 less than the Class A serviced amp you would not be financially embarrassed!

    I have bought Unc Nig's NJ321 and 729 cards! Just installed them in my 32.5 this weekend.

    They do not sound like the naim originals!

    They blow the whole soundstage wide open, the midrange becomes much more natural and looses its 'darkness.' The portrayal is probably more lively, although this effect is easing with use.

    I find the whole effect far more revealing, and I believe (in my system) it is a bigger upgrade than going from SNAPS to Hi CAP.

    I intend to run them for 3 weeks or so and then put the naim boards back in to see which I prefer.

    Dave
     
  20. sq225917

    sq225917 situation engineer

    That's because a PS upgrade is a relatively subtle thing compared to replacing the entire gain stage.
     

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