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It started with a broken switch- Nac12s/Nap160 refresh

Discussion in 'd.i.y.' started by Aussie Geoff, Jan 30, 2019.

  1. Aussie Geoff

    Aussie Geoff Member

    Hi all, First post on DIY pfm also posted in classic forum, wasn't sure which was appropriate. I recently unpacked my linn, naim, spendor bc2 system from storage ( linn naim owned from new . Nac12s No 0923, Nap160 No 1687, Linn lp12 No 14821) to find the black surround of the green on/off separated from the body of the switch. I took the lid off the nap160 to see what i could do and discovered badly leaking caps, all three.I have since replaced them, the tants on the boards, new switch with led globe and more , still keeping it as close to original. As a complete novice i was able to resurrect my 160 by trawling the pages of this great forum. I have no understanding of electronics but can follow instructions,diagrams and can do neat fine soldering ( jeweller by trade).
    Now i realise that my whole system is 40years old! So next project is my nac12s ( type 3 ). Once again lots of reading .Progress so far , new alps blue volume control,bypass the balance control and changed the 10uf 35v tants on the 321 iss2 and 324 iss3 boards. Now i am stuck ,i can't find any rock solid info on some of the other components that i feel probably need changing.
    I have noticed cracking and leakage on some of the maroon caps also does the blue 47uf 40v philips cap need changing on the 325 iss3 board. do the red 10uf 25v tants on the 322 iss1 boards need changing.What would be the appropriate replacements to keep the preamp as close to original.
    When this is sorted it will be the linn next, 40year old belt, 40year old oil in the bearing, etc
    thanks for any help.
     
    Svein, rontoolsie and booja30 like this.
  2. Jo Sharp

    Jo Sharp Pulls on doors marked push

    The maroon caps are Roedersteins and no longer produced. You might find new-old-stock on the web, but they might not be ‘as good as new’. There are plenty of good alternatives as feedback caps and a search through the diy forum or the acoustica web site will give suggestions. Some prefer substituting a film cap here and others will suggest a Nichicon electrolytic. I would replace the red tants in a preamp that old and a 10uf tant of 35V rating would be good here.
     
  3. Aussie Geoff

    Aussie Geoff Member

    Thanks for the reply and suggestions Jo. Six of the roedersteins look fine but the other six have cracks and seepage so i thought i might try some new /old ros just for the leaky six and leave the rest. I believe from reading here that the blue 47uf 40v phillips cap is on the relay board and might need replacing . I am still trying to get my head around different types of caps and their uses so i am pleased when somebody of experience suggests that a certain component is a good replacement.To be honest until i started reading these forums a couple of months ago i didn't really know any of the terms/ language used here. I will keep searching and learning. Its been very rewarding to get the nap 160 up and running.
     
  4. Jo Sharp

    Jo Sharp Pulls on doors marked push

    The relay electrolytic should be replaced....anything of same voltage and capacitance is fine. The tants are pretty much all the same....any of same value and voltage will be fine. Kemet are very suitable. You might want to experiment with film caps in the signal path instead of the 10uF tants, but this is a question of preference.
     
  5. Aussie Geoff

    Aussie Geoff Member

    Thanks Jo for your advice. I can get new/old roedersteins but they are a bipolar. I noticed that the originals have a polarity marked does that mean the bipolars are not suitable. The ebay seller asked if i was using them in the signal path or as filters as a novice i have no idea.i am replacing the three roederteins on the 322 iss1 boards. I will admit that i dont know what those boards even do. Complete novice here. Can anyone tell me if they are in the signal path or filters
     
  6. Aussie Geoff

    Aussie Geoff Member

    just worked out that the 322 boards are the moving magnet boards. But i still don't know if the maroon caps are in the signal path or used as filters.
    I can only get bipolar old/new roedersteins on ebay, are they suitable, the old ones are marked positive/negative.
     
  7. Jeff Young

    Jeff Young Well-Known Member

    Bipolar electrolytics are essentially back-to-back polar ones in a single can. So the main draw-backs are size and expense. But if they fit then they'll work fine.
     
  8. Aussie Geoff

    Aussie Geoff Member

    Thanks Jeff. They measure a little taller 16mm x 12.5 diameter, 5mm spacing and yes the seller is asking a premium for them !So when I fit them polarity is no issue? There twelve in total in my nac12s series 3 . Can these be used on all the boards that currently have polarised ones?
    Just double checking before pressing the buy button.
     
  9. neiljadman

    neiljadman Senior Member

    Beg to differ slightly from Geoff, yes if they fit they will work, but I always found them lacking and muddy in character. On building the NJ card series several of us auditioned a range of 47uF caps as alternatives to the ROEs, about 30 different types in all - I still have the box of caps tried. The Nichicon KZ 47uf/50v was by some distance the favoured choice being the closest to the original ROEs.

    On the 322s you have 2 feedback caps and both do exert significant influence on the sound. The third is the power rail cap, which can be replaced by an organic polymer cap: https://www.mouser.com/ProductDetail/Nichicon/PLV1H470MDL1?qs=sGAEpiMZZMsIwzbKW1rlgS36SLppdZPAv%2bTDRw7tJHk= They are very much worth trying.
     
    Aussie Geoff likes this.
  10. Aussie Geoff

    Aussie Geoff Member

    Did some research and read the same comment about mushy sound and also another discussing life span of new old roes. After much reading and advice I have gone with the nichicon KZ as suggested by Neil and many others. QUESTION can the kz's be used to replace all 12 roes in my nac 12. Or is it better to use an organic polymer cap on the power rails ?
    Another small problem as person with little understanding of electronics(the little bit gained from reading these pages) I don't know which roes do what job.
     
  11. neiljadman

    neiljadman Senior Member

    Geoff, you can indeed use the KZs wherever the ROEs were originally used - even in place of the axial cap on the 729s if you want to. And on the Naim circuits you can easily trace the power rail cap, from the power input, on the 322s, 321s and 729s, the first component is a 27R resistor, immediately after which the power rail cap runs between the power rail and ground. All others are feedback caps, 2 on the 322s, one on the 323s and none on the 729s. The exception is the 323 card, same principle applies but the 323 has an on board regulation, but the you'll find a 2k2 resistor and the power rail cap in series running to ground.

    Hope this helps.
     
    Aussie Geoff likes this.
  12. Aussie Geoff

    Aussie Geoff Member

    Thanks Neil very helpful, I should be able to follow these directions . I may use the same KZs for all the roe replacements as I have enough of them but it will be a good lesson for me to trace out the power rail and feedback caps.
     
  13. Aussie Geoff

    Aussie Geoff Member

  14. Jeff Young

    Jeff Young Well-Known Member

    Neatly done. Nice job!
     
  15. Aussie Geoff

    Aussie Geoff Member

    Well after checking dc offset and bias i finally plucked up the courage to attach an input signal ( yep thats a minidisk player, LP12 not running yet) and some speakers, ($30 logitech computer speakers ,just in case they went up in smoke ) Success! no hum ,crackles just music,now to hook up something better, i only have linn kans at the moment and no vinyl input yet. https://flic.kr/p/2djxo8H https://flic.kr/p/2djxob8
    My Spendor BC2 were sold when we down sized house,wish i still had them.
    Slowly getting there , now to research the lp12 .
     
  16. andyr

    andyr Registered User

    Now you've 'renovated' your 12s daughter boards … you may like to consider Ryan Sound Labs replacement boards.

    I did this to my own 12s and am very happy with what this swap did. :)

    Andy
     
  17. Aussie Geoff

    Aussie Geoff Member

    Yes i have read lots of positive comments about the Ryan boards. As i haven't really listened to anything that resembles real hifi for many years i think i will enjoy my "new " system for a while.
    When you have been away from it for a long time there so many areas that could be improved,i just have to convince the bank manager/ wife.
     

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