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Naim Nac 12

Discussion in 'classic' started by Svein, Mar 1, 2015.

  1. Svein

    Svein pfm Member

    I posted a photo of the Nac 12 instructions above. I got this Nac together with a Nap 120 as not working and one owner. When I opened the boxes I found that both units are never used. I can read from the boxes that the amplifiers in the first place are sent from Naim 11 Salt Lane to Linn Products.
    [​IMG]
    The Nac is working well, the 47uf/40v in the relay circuit is replaced with a Vishay of similiar spesification and the two Frako(?) capacitors in the 114 gain cards with nos Roe 47/40 as the original seem to leak (which they didn't and they measure ok aswell)
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    The orange Roe capacitors all seem ok. But I wonder about replacing the tantalum caps with new Kemet T356 35/40? What do you think? Keep it original? Any opinions?

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  2. Rallye_punk

    Rallye_punk pfm Member

    Nice example :)
     
  3. Svein

    Svein pfm Member

    Thanks Rallye_punk :) It's never used so it should be. I am very temted to replace the tantalum caps as I have many top quality Kemets here. The Frako caps are soldered back again so it's all original and working wonderful (apart from the capacitor in the relay circuit) The 12 is powered up by a Snaps now and I'll let it burn in for some days before I try it in the main system again.
     
  4. John_73

    John_73 pfm Member

    If it's never been used I'd leave the tantalum caps in place. Unlike electrolytics they don't really degrade over time if unused. Just leave it and enjoy it :)
     
  5. Svein

    Svein pfm Member

    Thanks John_73, I'll leave and enjoy it - for a while,-

    Right now I have a lot of fun with Nap 120s. One in great working order and the other may be sent for a service.
    [​IMG]
     
  6. John_73

    John_73 pfm Member

    Hi Svein. Just wanted to let you know a capacitor combination which has worked fantastically well for me in my Nac 12 cards. Unfortunately the original ROEs affer initially sounding great started to sound 'tired' and tonally rather grey for the past couple of months. I guess the caps were around 38 years old, and the Nac 12 when I first received it looked like it had had a rather rough life, so I guess it's not surprising they didn't hold up as well as I'd hoped & started to degenerate.

    Fortunately I found a combination that seems to loose absolutely none of the Naim 'groove' and really makes the sound blossom out of the speakers - it's a highly addictive full-bodied listen & really sparkles. Plenty of punch to the sound, but natural with strings & vocals with just a slight hint of warmth. I used the PFM favourite Nichicon KZ 47uF/50V for the feedback caps only, and Elna Cerafine 47uF/35V for all the psu decouplers. Seems to create a lovely balance. The Cerafines have been around so long now people seem to ignore them, but they work fantastically well as decouplers here. I used fresh production caps all from Hi-Fi Collective.

    John.

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    [​IMG]
     
  7. yurivv

    yurivv pfm Member

    An interesting finding, John, thanks for sharing.
     
  8. John_73

    John_73 pfm Member

    You're welcome Yurivv! :)
     
  9. Svein

    Svein pfm Member


    Hi,
    thanks John. I have a bag of the Nichicon KZs here and just ordered some Cerafines. Always interesting to try out new combinations and think soldering at this level is good fun aswell,-
    The best sound I have got out of my Nac 12 so far are via a pairs of 324/7 and 321/2 recapped with NOS Roedersteins 47uf/40v (zitronen_eis/ebay) and Kemet T356 tantal capacitors. This give a very fast, dynamic and super enganging sound with a Nap 120 and SBLs.
    Right now I use a set of RSL boards in the 12, kindly lent to me from a Norwegian enthusiast.
     
  10. John_73

    John_73 pfm Member

    No problem - I'll be interested in your opinion of this combination. I love this sound so much I'm going to order spare caps for future use if ever needed. I'm also using the Kemet T356 tants in my Nac 12 too. They really are perfect for Naim recaps.
    There is one problem with this combination: I am listening to too much music now ;)
    How do the RSL boards sound in the Nac 12?
     
  11. Svein

    Svein pfm Member

    Yes, I'll let you know what I think about this combination.
    The RSL boards are great. Smoother and more resolved than the 324/321 combination without losing much of the original qualities. Maybe a little less dynamic and sharp on transients. All kinds of rock are very interesting with the RSL cards. But I'll give 60% of that credit to the Nap 120. That amplifier is unreal. I may try go active into SBLs with two of them in the future. I recall you had a Nap 120 project, tested the amplifier?
     
  12. John_73

    John_73 pfm Member

    Yes it was a real mess, inside and out. I've had the chassis shot blasted and powder-coated and it looks like new, and have completed repair of the pcbs. An illness means I can't devote much time per day to diy audio unfortunately, but I'm hoping to get it all back together & rewired over the summer months. The pcb looks almost the same as the bolt-down Nap160s, with the advantage that output transistors are mounted directly of course, not on flying leads as per the 160. That might give it a slight advantage, plus it has the frame type transformer. I look forward to doing a comparison between the 120 & 160 at some point.
     
  13. Svein

    Svein pfm Member

    Hi John,
    good to read the Nap 120 project is in progress.

    I tried your receipt with the Nichicons and Cerafines after the latter arrived here last Monday. I think the sound is fast, dynamic and groovy just like you describe. It's quite similar to the original Naim sound. With the Roe capacitors I think the bass is better defined and the sound as a whole is more colorful. But all in all more similarities than differences. Thanks for sharing.
     
  14. John_73

    John_73 pfm Member

    The ROE capacitors are fabulous, without a doubt. I have a pack of 20 NOS kept just incase I change my mind again ;)
    In a perfect world I'd have twin sets of cards so I can change the voicing when I feel like it.
    I've noticed the KZs take a few days from new before they really shine, subjectively. Before that they can sound a little 'light-weight' and congested. The Cerafine technology seem very well suited to psu use, though I wouldn't use them directly in the signal path. The combination of KZs and Cerafines works superbly well for my tastes.
    Look forward to seeing more of your Nap120 adventures.
     
  15. John_73

    John_73 pfm Member

    After a LOT of listening, I've changed to NOS ROEs for the feedback caps Svein. You're right about their powerful lower bass, and that lovely full sounding slightly colourful midrange. The sound blossoms with the ROE types. But I've remained with Cerafines for the 24V psu rail positions - I think they're superb here. The KZs are still fantastic caps, but I wonder if the lack of an aluminium case gives the ROEs their subjective audible strengths... I have also noticed too that although they say 47uF, they're often higher than that, whereas the KZs are often at or slightly below 47uF. Might be the reason for the bass being a little fuller with the ROEs.
     
  16. Svein

    Svein pfm Member

    Lot of listening here also. The 12/120 has a dynamic and rythmic sound with a pace and drive it's hard to resist. I'll try the Cerafines as in you description later on. It's certainly good caps. The Nac 12/3 in daily use was like new when I bought it. The motherboard is issue 2. All capacitors on the 324 and 321 cards are 'Roe'. I promised myself to never touch the cards, but during easter I removed all the capacitors and measured them. All were within spesications, the Roes measured like the NOS bought on Ebay, between 50-55uf, esr 0.5-0.6 ohm. Same with the green Roe 'ERO' tantals, all between 10-12uf and esr around 0.5 ohm. I soldered them back (with 33 Tri-sol solder from the 1970s i got from my father) after taking notes and making the best possible symmetry, and using the caps close to the specs in the signal path. The cards are still in the 12 and sounds very good.

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    [​IMG]
     
  17. Svein

    Svein pfm Member

    An enthusiast gave me some more info on the Nac 12.

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    [​IMG]
     
  18. wylton

    wylton pfm Member

    I have two NAC 12's up in the workshop, waiting for me to decide what to do with them. I have a NAP 120 too; I'll post up some pics when I get a chance.
     
  19. divedeepdog

    divedeepdog pfm Member

    I've got an updated 12 according to the information (Class A serviced). Slip it into the system every now and then. Majors on pace and attack and oddly sounds more 'hi-fi' than my Avondale 102, even with 821's in it.
     
  20. wylton

    wylton pfm Member

    Interesting you should say that, I have a standard (albeit Avondale powered) NAC 102 in my main system. In the office system, the NAC 12 will have to compete with a NAC 42.5/Avondale TPR4 upgraded Hi-Cap.

    I intend to keep the NAC 12's as standard as possible.
     

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