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DIY Naim NAC 72/ 82 Recap - Capacitors

V

Van

Tinkerer82
Hi I have a trusty 72 and like to get it recapped. I'm fairly hands-on so would like to attempt it myself. I think soon after doing my 72 I might attempt an 82 as it seems to share similar

47uf 40v - qty 3
47uf 50v - qty 6
10uf 35v - qty 12 (kemet) T368?? Tantalum

Does anyone know where I can source these reliably? Ie not ebay or amazon.
Been looking at mouser or cpc farnell but too many choices.

Which brand, temperature, tolerance, or even part number or even a link would be useful.
I scoured the pages but couldn't find any answers. Thanks in advance
 
The following assumes you want to keep the original Naim sound. I believe you’re are asking about servicing, which means restoring to new rather than changing. The alternative is to replace the boards with ready-made Ryan Sound Lab ones, which are often favoured here. Generally, there’s no point in servicing a NAC72 unless it’s not working correctly. Simply pulling out / pushing back in the boards and DIN plugs is generally restorative.

The NAC72 contains mainly tantalum bead capacitors. These do not “go off” with age, unless one of them becomes short circuited, in which case the preamp would not work or it would sound crackly. You could replace the whole lot with AVX 35V 10microF tantalum bead if you were obsessive enough, though I’d not bother.

The other capacitors are aluminium electrolytic and the type used depends on the age of the preamp. If it contains red-can ROE capacitors, then do no replace these, as they are no longer made but they have a certain character of sound that I would want to keep. They should last forever too, as long as the yellow resin seal below them has not cracked (removing them may crack them). Alternatively, they may contain blue Samwha 47microF 35V or 50V, which could be replaced with Nichicon MUSE UKZ, which sound similar in my opinion. The same applies to any yellow electrolytics. The value tolerance is not important and they need to be at least 35V (given the supply voltage is 24V).

Using alternative capacitors / boards will change things radically. Whether that’s for better or for worse is a matter for your own opinion. There are multifarious articles discussing this matter here.
 
What a load or utter tosh!

The used equipment I've owned over many years has often benefitted from servicing to a quite considerable degree. It all depends on how its previous owners have used it, and in particular whether they bought into the Naim "leave it on 24/7" philosophy. Power amps are also heavily influenced by how hot the previous owners ran them.

Preamps are the least likely to "need" servicing in most cases but the capacitors do age and wear out.

I'm just about to fully service my 2002 Naim 82 for the second time, and I know it needs it because I also run a quad railed 42 which I serviced a few years ago and use very little, and over the last year or so it's become obvious that the 82 has lost a little "sparkle".

Electrolytic capacitors have a definite lifetime so should be replaced occasionally if the equipment is regularly powered.

Tantalums theoretically have infinite life, but in practice the sound is often improved in clarity by replacing them. It is not clear whether this is some form of ageing or just that the tantalum caps Naim used in the past weren't actually very good. Certainly I've found that replacing STC manufactured ones is generally beneficial, whereas replacing the big red ones, NEC blue ones or later Kemet yellow ones isn't always. None the less Naim and their authorised service agents normally replace them all.

Unfortunately they've gone a bit pricey recently and are over £2 each now.

You can't replace anything with an "exact" replacement and people make all sorts of arguments for how one brand of cap sounds better/worse/different from another in particular positions.

For the 72 a conventional choice is to replace all tantalum caps with Kemet or AVX branded units and replace all electrolytics (both axial and radial) with Nichicon MuseKZ 50V caps.

The best way to know for sure if your amps need servicing is to try to arrange a bake off against ones which have been serviced. If you can hear a significant difference then you have the answer!
 
I'm with colasblue on this one, I recapped my NAC32.5 and after I got bored of it because it sounded dull and lifeless, made a real difference and brought it back to life. I decided to replace caps "like for like" as close as I could so no mods.

Tants - Don't know what the originals were but I replaced all of them with Kemet T356 series
Electrolytic radials - ROE originals, replaced with Nichicon Muse KZ series, be careful because the KZs are taller than original ROEs or Samwas and the top could touch the solder side of the board next to it (you'll see what I mean when you do the job). I just glued small nylon bar to PCB edge clips to to create spacers and keep pairs of boards separated.
Electrolytic axials - Nichicon TVX series, but in 32.5 these don't have anything to do with signal so specs aren't important.
Inspect all PCB plug in pins and edge sockets, clean with IPA or contact cleaner and plug boards in/out a few times, any doubtful edge connector sockets should be replaced, I could look up the p/n and a source for you but I don't have it to hand.
DIN and BNC sockets - Inspect, and clean with a small amount of contact cleaner and reseating cables a few times, replace any doubtful ones with new Preh ones - but now you're getting into a world of hurt as they are fiddly to replace while maintaining the nice tidy Naim wiring.
Use leaded solder if you can get it, it's easier to use than silver solder, and unless you really know how to solder I wouldn't suggest doing any of this at all, I see some really shitty soldering "blob-a-jobs", dry joints, lifted lands and tracks and it makes me sad to see nice equipment butchered by people who think they know how to solder.

I get all my components from Farnell (Newark Element 14 here in Canada), Digi-key or Mouser depending on price/availability, I would use RS but they don't work out well for Canada, these are all large respected electronics supply companies so you can be as sure as is possible that they will supply genuine parts. I would never use ebay or alibaba or such like for commercially available components, although sometimes if you are looking for NOS / obsolete / niche parts you have to take the risk.
 
colasblue said:
I'm just about to fully service my 2002 Naim 82 for the second time, and I know it needs it because I also run a quad railed 42 which I serviced a few years ago and use very little, and over the last year or so it's become obvious that the 82 has lost a little "sparkle".
Click to expand...

I also have an 82 which I "serviced" some years ago when a tantalum capacitor went short circuit and dumped 6 volts dc on one channel's output, traced and cured with the aid of advice from yourself and Martin Clark as I recall.
The guilty capacitor has been replaced again since and now needs replacing once more! The replacements were from a bag of 100 AVX 10 mic 35 v items bought from an ebay seller in Taiwan that I remember you had used and thought a reliable source (Taiwan is home to AVX after all).
I also have a 4 rail 42 which has very occasional use so I must try doing a comparison as you have done.

Having enjoyed reading your NAP 135 servicing thread (now preserved in the "Reference" section) is there any chance of you doing a similar thread for your 82 service?
 
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Sounds like a decent enough idea.

It won't be in the short term though since I've a couple of bathrooms to finish installing first!

I've got some NoS Oscons which might find their way into the 82 re-cap and am minded to try replacing tants with wima films and doing something close to MJS's superlink mod so I'm likely to end up with a pretty non standard 82.

Maybe I'll get a second sample and do one "standard" and one not to really explore the differences. They've got just about cheap enough to consider that.
 
Some p/ns for your NAC72, just search Digikey / Farnell / Mouser / RS for best price, shipping, availability etc. A lot of the p/n variations are just suffixes and are for packaging and wire form which is important for manufacturing and machine insertion, but all you need to buy is individual (often called bulk) capacitors, you don't want an ammo pack of 5000!!!! -

10uF 35V 5% radial tantalum - Kemet T356G106J035AT
10uF 35V 5% radial tantalum - AVX TAP106J035
47uF 50V 20% radial electrolytic - Nichicon Muse Gold UKZ1H470MPM
Or you could try Elna Silmic II for the radial electrolytics, some people like these and they are shorter than the Nichicons - Elna RFS-35V470MH3#5

Just a starting point for you, but you can buy whatever brand you want.
 
One word of advice re Silmics (which I've used to date in most previous recaps) is that they have quite a long run in period, so don't expect instant results unless your kit is pretty well gone. It typically takes 4-6 weeks for kit to come fully "on song". I observed this with a Snaxo-2-4 which improved over that period to the point where it took over from the predecessor Naxo 2-4, and I'm sure it wasn't just my imagination or my ear becoming accustomed to the slightly different character.

I can't comment on the MuzeKZ directly since my most recent recaps pre-date it (I did say I'm ready to do it again!). I'm certainly going to try them out.

The original Sanyo Oscon SP, in contrast offers instant gratification, but is, unfortunately, long out of production.

Changing tants gives instant results if it's going to make any difference.

Both the Muse KZ and Silmic II are available from hifi collective and currently at prices that better major suppliers.
 
Good Morning All,

OS-Con's are available here - https://www.ebay.com/itm/1721767459...d=link&campid=5338728743&toolid=20001&mkevt=1

There is a place in Canada selling 22uF/ 63V Roedersteins if you want (Parts Connexion).

Elna Silmic II's are cheapest from Digi-Key but obviously you need to make up a sufficiently large order...... I ordered a bulk lot of 10uF/ 50V (20off) and 100uF/ 63V's (50off) but neither of these values will be of use to you.

Regards

Richard
 
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Are you sure those OS-cons are actually genuine Richard?

That ebay seller has been around for a while and seems to "miraculously" have limitless quantities of all sorts of otherwise unobtainable parts.

The picture isn't 100% convincing since his Oscons have nickel plated round profile legs, but my genuine ones (from a past PFM group buy) have unplated copper legs.
 
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Thanks to everyone for their in-depth responses. Thanks Avon, I think it's more of a want than a need to recap. I got a bit of OCD so like to do it myself and get it done anyway. Some really good restorative tips. These older naim pre amps are not so onerous to recap. Really appreciated all who have replied with the details of the components. I hope it can be a reference for other people to use. I know for some who are outside the UK it's difficult to have it send back to naim for a recap so this at least provides options for those who are willing to dare.

Colasblue, for the 47uf 40v .... would Nichicon MuseKZ 50V caps work on these, or do they need to be the same voltage? You got the part number for these?

I'm from the UK and the names of those suppliers are helpful. If I can help it I try to buy from a reliable source.

Now got a reason to buy a engineer SS-02 desoldering pump lol.

For ref just for the 82 you just need these:
47uf 40v qty 8
10uf 35v qty 24
 
The Nichicon Muse 47uF/50v will be absolutely fine. Use them for power rail decoupling/filtering.
Use 47uF/35v Elna Silmic IIs for the feedback caps.

HiFi collective are very good. They definitely kept us going when my workshop was literally round the corner from them a few years back.
 
I could not find the Kemet or AVX on Hifi Collective. However, elsewhere the Kemet are really expensive. The AVX is a cheaper choice but any compromise in quality?

10uF 35V 5% radial tantalum - Kemet T356G106J035AT - £5
10uF 35V 5% radial tantalum - AVX TAP106J035 - £1

MJS, your comment 'Use 47uF/35v Elna Silmic IIs for the feedback caps'... are you saying use this in place of '47uf 40v'
 
colasblue said:
What a load or utter tosh!
Click to expand...
Please do not make comments such as this. They make PFM a very unpleasant place to be.

The point I was trying to make is that it’s unnecessary to service Naim preamps every ten years regardless. The only exception to this is if you know the preamp isn’t performing optimally. However, unless you have another to compare it with, then this is a very difficult judgement to make. The difficulty comes from not knowing.

Obviously electrolytic capacitors do degrade with time and they are more likely to need replacing than tantalum capacitors would. However, when I replaced the gain board Samwha feedback capacitors in my 30-year old NAC72 with new Nichicon MUSE UKZ, it sounded similar but not better or worse. Also in my opinion, there was marked improvement from adding 30-year old ROE maroon electrolytics.

The amp had been powered up more or less continually for 30 years. Are my observations towards longevity unusual?
 
Maybe a bit OT, but I wonder what caps are those transparent films Naim uses in some places such as TDA1541A decoupling, phono boards, also sometimes as the zobel cap on NAP250 boards...? AXV CB PEN, Panasonic ECHU and TDK EPCOS B32560/B32562 look similar, but what's the closest replacement type for what Naim uses?

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Those are 'stacked-film', polyester caps.
Superb for what they are used for; easy to find NOS from second-sources, and cheap.
Else I'd look at Wima MKS2/mkp and similar (Vishay has a wide range of comparable parts) for the same tasks.
 
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Van Nguyen said:
I could not find the Kemet or AVX on Hifi Collective. However, elsewhere the Kemet are really expensive. The AVX is a cheaper choice but any compromise in quality?

10uF 35V 5% radial tantalum - Kemet T356G106J035AT - £5
10uF 35V 5% radial tantalum - AVX TAP106J035 - £1

MJS, your comment 'Use 47uF/35v Elna Silmic IIs for the feedback caps'... are you saying use this in place of '47uf 40v'
Click to expand...

Some things are just at crazy prices currently. I personally don't think there's any difference between the sound of AVX and Kemet tants. Or for that matter the old blue NEC tants or Panasonic tants. The tolerance is not in any way critical so you can save a but by using a 10% or even 20% series.

£1 each is currently a very good price.

The feedback cap isn't the gold axial one on the time aligned board, it's C5 on the gain board (pic courtesy of Martin's site)

http://www.acoustica.org.uk/t/naim/preamp_pics/gain_board_pic.jpg
 
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