Naim NAIT 2 Restoration Project

[laverda]

Progress is being made on my Nait 1..

The transformer installed is an over the top at 21 0 21v secondaries. I recall the Nait 1 rails should be + - 22vdc, this one will have rails at + - 29vdc. I checked there's no components that 'cant' handle the 29vdc, but we'll see. The output devices are MJE5030 and 31, the vol pot Blue Alps is 20k and Im not sure on the balance load, Ive dropped some 6k in there but not sure the orientation is correct but thats an easy fix if I their wrong.

On power up nothing got hot and after 15mins the offset was less than 10mV on both channels.

Some final fettling and sound test.....

 

[badlyread]

Another huge win - if you find it has too much gain then snip the 1k resistor in line with the 47uF feedback cap in the preamp. The gain stage is now a buffer instead and can use far more of the not-very-well-tracking volume pot.

Can someone please show the position of this resistor in a photo. Many thanks.

 

[OzBrit Audio]

The output devices are MJE5030 and 31

Looks like someone has converted this to fully complementary output devices not the standard NAP quasi complementary...

Be interesting to hear how this sounds

 

[MJS]

The NAIT1 was fully complimentary.

Can someone please show the position of this resistor in a photo. Many thanks.

IIRC it's the 1k resistor in series with the +ve end of 47uF maroon caps nearest the volume pot.

 

[OzBrit Audio]

Is

The NAIT1 was fully complimentary.

IIRC it's the 1k resistor in series with the +ve end of 47uF maroon caps nearest the volume pot.

I didn't realise that about the Nait 1. So the Nait 2 changed the design to quasi complementary but not so in the original Nait?

 

[neonixcool]

Is

I didn't realise that about the Nait 1. So the Nait 2 changed the design to quasi complementary but not so in the original Nait?

Good day
The Nait1 and Nait2 is same schematic

 

[neonixcool]

The black Nait5i it’s a different schematic

 

[OzBrit Audio]

Good day
The Nait1 and Nait2 is same schematic

I don't think so if the Nait1 is fully complementary.

Here is the Nait2 schematic

https://www.hifiaf.com/wp-content/uploads/2020/06/49952781032_f57ea6336e_o.png

Not a complementary output stage on the Nait 2.

 

[Yank]

The NAIT1 was fully complimentary.

So, Naim's most advanced design...

 

[TimF]

I know my Nait complimented me on a few occasions, it said "Nice choice of tunes, mate!", and played on.

 

[Craig B]

Did it sound like Chris Franklin?

Ben Sidran?

 

[Avon]

Another huge win - if you find it has too much gain then snip the 1k resistor in line with the 47uF feedback cap in the preamp. The gain stage is now a buffer instead and can use far more of the not-very-well-tracking volume pot.

Please don't do this. Yes, it'll reduce the gain, but it'll change the sound such that the boogie factor is gone. I'm basing this on my own experience of changing the gain boards in Naim pre-amps.

 

[neonixcool]

I don't think so if the Nait1 is fully complementary.

Here is the Nait2 schematic

https://www.hifiaf.com/wp-content/uploads/2020/06/49952781032_f57ea6336e_o.png

Not a complementary output stage on the Nait 2.

Nait1 and 2 is same

Nait2 just PC design of board

 

[neonixcool]

Nait3 have a same power amp schematic but preamp is different

 

[MJS]

NAIT1 and 2 are not the same.
Nait 3/NAP90 is mostly the same amp circuit as the NAIT2.

 

[OzBrit Audio]

Does anyone have the schematic of the Nait 1 power amplifier stage which I now understand has fully complementary output stage?
Curious they jumped to quasi complementary in the Nait 2 and back to complentary again in the Nait 5.

 

[deltaunit]

Link to PDF

Needs checking but comments welcome.

 

[neonixcool]

Good day
Correct it’s my mistake
I check again the board of Nait1 and output stage is not quasy
His is are emitter repeater
Sorry
Nait1 and Nait2 is not same by output stage

 

[neonixcool]

Nait1 and 2 is same

Nait2 just PC design of board

in attachment the Nait2 schematic