Nait 1 Service

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hifiaf
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Re: Nait 1 Service

Post by hifiaf »

You're incredibly generous with your time, Will. And I see from another thread that you've been working full-gas through the lockdown, too. Thanks for all this!

Nobeone
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Joined: Sun Mar 29, 2020 8:32 am

Re: Nait 1 Service

Post by Nobeone »

Hi Tom,

I would have expected the phono stage to be much like the 3 series MM card, but I would have to look that up, my guess: it is missing the constant current sink transistor pair on each gain section.

AMP is the original company, blade I guess is the trade name for that type of connector. I imagine there are lots of other companies that make compatible or similar parts. Sorry I don't have part codes for the blades or connectors to hand.

Kans and ESL57s, fantastic! If Mrs Nobeone would ever accept them, I would love some ESLs!
Last edited by Nobeone on Wed May 27, 2020 6:27 am, edited 1 time in total.

Nobeone
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Re: Nait 1 Service

Post by Nobeone »

hifiaf wrote:
Wed May 27, 2020 3:45 am
You're incredibly generous with your time, Will. And I see from another thread that you've been working full-gas through the lockdown, too. Thanks for all this!
:D I have this information, it needs sharing so people can keep their Naits working without spending an arm and a leg on AV Options or Naim, older kit like this was made for maintaining, it needs keeping working not sending to landfill ...

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YNWaN
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Re: Nait 1 Service

Post by YNWaN »

hifiaf wrote:
Wed May 27, 2020 3:45 am
You're incredibly generous with your time, Will. And I see from another thread that you've been working full-gas through the lockdown, too. Thanks for all this!
Yes indeed, many thanks for all your input :).
Mark

TomB
Posts: 59
Joined: Tue Apr 07, 2020 5:06 am

Re: Nait 1 Service

Post by TomB »

Nobeone wrote:
Wed May 27, 2020 6:27 am
hifiaf wrote:
Wed May 27, 2020 3:45 am
You're incredibly generous with your time, Will. And I see from another thread that you've been working full-gas through the lockdown, too. Thanks for all this!
:D I have this information, it needs sharing so people can keep their Naits working without spending an arm and a leg on AV Options or Naim, older kit like this was made for maintaining, it needs keeping working not sending to landfill ...
Thanks again Will, both for feeling this way and sharing this information. I could not agree more about providing people an option that allows them to to keep these Naits working without spending an arm and a leg to do it. Well put.

Nobeone
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Joined: Sun Mar 29, 2020 8:32 am

Re: Nait 1 Service

Post by Nobeone »

Bit more progress, I have now added the relay circuit, again for ease I just used a random inductor for the coil in the relay for the schematic and I couldn't find BZY88C 10V so I put a BZX84C10VL for convenience, same difference ;)

(EDIT: updated with later more complete schematic)

ImageNait2 schematic phono stage, PSU, relay, preamp by Will Moore, on Flickr

And marked that up on TomBs Nait1 photo, I can't tell what the diodes really are are and I may have a few component idents swapped but a decent first stab given I don't have a Nait1 in my hands!

(EDIT: update with later more complete markup)

ImageNait1 phono stage, PSU, relay, preamp markup by Will Moore, on Flickr

The only additional component for service this marks up is C75 which I have to say doesn't really matter, it is just charged up to provide an RC time constant delay on power on before connecting the pre-amp output to the power amplifier while everything stabilises. For convenience we can make this the same as the cheapest 47uF cap we use in the rest of the recap. The schematic marks it as a 35V part, which is odd, as it will not see much more than 17V?!!? Anyway. Nothing to see here, the dullest, least signficant cap on the board probably, nil influence on sound, except: when I got my Nait2 out of the loft before I sold it I found the relay was not firing, no sound, just needed running for a bit to re-form the cap then it worked a treat and was duly sold/swapped for my NAXO 2-4. However the purpose of the tale is to say this part does age and can give trouble and so needs replacing as part of a service even though it has nothing much to do with sound quality as long as it can hold enough charge to switch the relay on!
Last edited by Nobeone on Thu May 28, 2020 5:40 pm, edited 2 times in total.

Nobeone
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Re: Nait 1 Service

Post by Nobeone »

Something it took me a while to notice, C72 on TomBs Nait1 is a radial cap "bodged" in to an axial position. Seems a bit crap to me.

EDIT: re-written to remove my confused nonsense.
Last edited by Nobeone on Wed May 27, 2020 10:00 pm, edited 1 time in total.

TomB
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Re: Nait 1 Service

Post by TomB »

Nobeone wrote:
Wed May 27, 2020 6:22 pm
Something it took me a while to notice, C72 on the Nait1 was clearly a radial cap by design, and we know originally it was 2200 uF on the Nait1, 3300 uF axial on the Nait2. If Naim service use the same parts on both now, and we have reason to believe from the Naim forum thread I posted that they do, then they are "bodging" in an axial much like in TomBs Nait1. Seems a bit crap to me. Might be better looking for a 3300 uF radial cap for the Nait1, it will be easier to fit, less of a bodge, and a lot cheaper with a lot more choice of better caps. Axial are odd balls nowadays.
I read this again and I am a bit confused. I thought the this cap was originally an axial and that the radial was bodged into my Nait 1?

It looks petty bad in my Nait. And you may notice that it was stabilized to the board and to the rectifier bridge with a glop of some lovely silicon. I bought a 3300uf 25V Kemet (PEG226HJ4330QE1) axial from Mouser. It seems like a good choice. The can is not insulated, but since this is the negative side of the cap, i see no need to insulate it. Is there any need to insulate it? If this axial cap seems like a good choice, I will add it as an additional possibility to the Nait 1 BOM.
Last edited by TomB on Wed May 27, 2020 9:16 pm, edited 1 time in total.

Nobeone
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Re: Nait 1 Service

Post by Nobeone »

Hmm I got this wrong. Your Nait1 photo is showing a radial bodged in to an axial position for C72. I thought the link wire by BR1 was a lead from an axial bodged in to a radial position but it isn't is it, it is a link wire? I think I am tired!

Hmm, uninsulated it is a large amount of metal to short on, U1 is the LM317, R77, D70 and that link wire out of BR1 all pose a risk if it moved about, or if clearance is very small to the new part. Try it and see, if there is some decent clearance when you fit and you get it nice and tight to the board, an axial in an axial position it isn't going anywhere. If clearance is tight, slip some heat shrink on?

TomB
Posts: 59
Joined: Tue Apr 07, 2020 5:06 am

Re: Nait 1 Service

Post by TomB »

Nobeone wrote:
Wed May 27, 2020 9:10 pm
Hmm I got this wrong. Your Nait1 photo is showing a radial bodged in to an axial position for C72. I thought the link wire by BR1 was a lead from an axial bodged in to a radial position but it isn't is it, it is a link wire? I think I am tired!

Hmm, uninsulated it is a large amount of metal to short on, U1 is the LM317, R77, D70 and that link wire out of BR1 all pose a risk if it moved about, or if clearance is very small to the new part. Try it and see, if there is some decent clearance when you fit and you get it nice and tight to the board, an axial in an axial position it isn't going anywhere. If clearance is tight, slip some heat shrink on?
You answered as i was editing my message :) After I read it again, I was a bit confused. Thanks for your insight about the cap insulation. The negative side would be at ground but I see your point.

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