View Full Version : NAC Servicing


Southgate
19-04-09, 10:57 AM
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.

sq225917
19-04-09, 11:03 AM
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?

Southgate
19-04-09, 11:12 AM
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.

binnie
19-04-09, 11:16 AM
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

misterc6
19-04-09, 11:18 AM
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.

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

binnie
19-04-09, 11:31 AM
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

Southgate
19-04-09, 11:36 AM
So are most/all the service components contained on the replacement 321 and 729 cards?

BobMaximus
19-04-09, 12:14 PM
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.

The Captain
19-04-09, 12:40 PM
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.

Southgate
19-04-09, 12:40 PM
If these cards were changed for new ones, would there be anything else left to change?

The Captain
19-04-09, 12:43 PM
well yes the 324 cards and phono cards ideally need a tickle too.

Southgate
19-04-09, 12:51 PM
I thought the NJ 321 and 729 cards still keep the 'naim sound'?
Whereas the Avondale mods tend to alter the naim presentation more?

flatpopely
19-04-09, 12:54 PM
I thought the NJ 321 and 729 cards still keep the 'naim sound'?
Whereas the Avondale mods tend to alter the naim presentation more?

Correct on both counts.

BobMaximus
19-04-09, 01:00 PM
I thought the NJ 321 and 729 cards still keep the 'naim sound'?
Whereas the Avondale mods tend to alter the naim presentation more?

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

misterc6
19-04-09, 01:20 PM
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

BobMaximus
19-04-09, 01:26 PM
medicinal brandy

I've got some isopropanol. Will that do?

misterc6
19-04-09, 01:43 PM
I've got some isopropanol. Will that do?

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

uncl_nigel
19-04-09, 02:08 PM
It depends on who you choose to believe. I have learned to believe no one.

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

batjodel
19-04-09, 11:54 PM
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

sq225917
20-04-09, 06:30 AM
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.



Dave

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

uncl_nigel
20-04-09, 09:32 AM
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

I wondered who had got them :D
I would agree with what you say, I just preferred the Avondale boards.

So far the only pre I have heard that is instantly noticably superior to the 72 with 821A boards cost 7000 Euro (about 12 times more than an ebay 72 + 821A boards).