Naim Nait-2

etsang3 · 6th December 2005, 01:10 PM

I am helping my friend to modify Naim Nait-2 int. amp.
I may post photos after the job is finished.
Here is the circuit I would like to share.

etsang3 · 6th December 2005, 01:11 PM

Naim Nait-2 Line amp

etsang3 · 6th December 2005, 01:13 PM

Naim Nait-2 Power-amp Stage

lohk · 6th December 2005, 01:27 PM

These are schematics of the old (and famous) NAIT 1 (a scaled down version of the bigger cousins). Why do you want to modify the historical gem?

(Maybe the PSU caps have to be replaced because of age.)

etsang3 · 6th December 2005, 02:03 PM

Hi, lohk

(Maybe the PSU caps have to be replaced because of age.)
Yes. what we call the modification is mainly replacing the old cap to some Audio Grade new cap. We maintain the old value too.
Add some caps at the legs of the power transistors which are connected to the filter caps. The circuit tracks of that portion are quite long and thin.

HOEK · 6th December 2005, 05:30 PM

hello

what is the voltage for the units?
Can you show a schema of the PSU

thanks

martin clark · 6th December 2005, 07:39 PM

The PSU is a simple centre-tapped 120VA transformer, 18-0-18VAC, with a bridge rectifier and 6300uF, 40v caps. There is a separate rectifier stage for the line amp stages.

I've a bit more info on servicing the Nait 2 here:
http://www.acoustica.org.uk/t/nait/nait2.html

lastguy · 6th December 2005, 11:57 PM

from the circuit the product design seems lower than average. Don't know how it become so famous.
A famous magzine editor used to say: DIY HiFi is a big lier, when XXX put a market a class B everybody say good, when you spent $xxx to buy a speaker wire, you get to lie to yourself it is better.

etsang3 · 7th December 2005, 02:01 AM

Hi lastguy, you may be right, more right. I am a DIYer and an EE for many years. At the beginning, I cannot believe and explain that such lower than calculation amp can sound good. But if you have listened to it. You will be amazed by it musical performance. (but with limitation). When you use it to play Pop or rock music, it is a total different story. It can't perform those material. Rock music sound like classical music (I consider). Nait capabilities are on those chamber, single instrument, vocal, light jazz and vocal music etc... I assume, it accurate and clean musical performance is due to its simple design (only 3 or 4 stages), low amount of negative feedback (open-loop gain is not high) and low power consumption (just 20mA idle current at the O/P transistor !).
If you are enjoying the music contents within Nait-2 list, you'll like it and keep using it for long years. It can't work for you for those louder American Country music (e.g. Thank God I am a Country Boy) nor Pop music (e.g. Bad, the Sad Cafe ) nor Big Symphony (e.g. 1812, Beethoven No. 5). My friend use it for years but I like the kind of music not on the Nait-2 list so I built a Class A 100W to listen to virtually all music or signal or noise.

amplifierguru · 7th December 2005, 03:55 AM

Hi etsang3,

My... all those electros in the signal path AND the very ordinary topology with poor supply filtering and PSRR.

No wonder it becomes easily confused on complex passages.

Hi lokh,

...."Why do you want to modify the historical gem? "

Gem.. hahahaha.

Have to agree with last guy.

Cheers,
Greg

6th December 2005, 01:27 PM	#4
lohk diyAudio Member Join Date: Apr 2001 Location: Austria, near Linz	These are schematics of the old (and famous) NAIT 1 (a scaled down version of the bigger cousins). Why do you want to modify the historical gem? (Maybe the PSU caps have to be replaced because of age.) __________________ /alohka/

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6th December 2005, 02:03 PM	#5
etsang3 diyAudio Member Join Date: Feb 2005 Location: Hong Kong	Hi, lohk (Maybe the PSU caps have to be replaced because of age.) Yes. what we call the modification is mainly replacing the old cap to some Audio Grade new cap. We maintain the old value too. Add some caps at the legs of the power transistors which are connected to the filter caps. The circuit tracks of that portion are quite long and thin.

6th December 2005, 05:30 PM	#6
HOEK diyAudio Member Join Date: Apr 2005 Location: Burgum	hello what is the voltage for the units? Can you show a schema of the PSU thanks

6th December 2005, 07:39 PM	#7
martin clark diyAudio Member Join Date: Jul 2003 Location: Bath, UK	The PSU is a simple centre-tapped 120VA transformer, 18-0-18VAC, with a bridge rectifier and 6300uF, 40v caps. There is a separate rectifier stage for the line amp stages. I've a bit more info on servicing the Nait 2 here: http://www.acoustica.org.uk/t/nait/nait2.html

6th December 2005, 11:57 PM	#8
lastguy diyAudio Member Join Date: Dec 2005 Location: CA	from the circuit the product design seems lower than average. Don't know how it become so famous. A famous magzine editor used to say: DIY HiFi is a big lier, when XXX put a market a class B everybody say good, when you spent $xxx to buy a speaker wire, you get to lie to yourself it is better.

7th December 2005, 02:01 AM	#9
etsang3 diyAudio Member Join Date: Feb 2005 Location: Hong Kong	Hi lastguy, you may be right, more right. I am a DIYer and an EE for many years. At the beginning, I cannot believe and explain that such lower than calculation amp can sound good. But if you have listened to it. You will be amazed by it musical performance. (but with limitation). When you use it to play Pop or rock music, it is a total different story. It can't perform those material. Rock music sound like classical music (I consider). Nait capabilities are on those chamber, single instrument, vocal, light jazz and vocal music etc... I assume, it accurate and clean musical performance is due to its simple design (only 3 or 4 stages), low amount of negative feedback (open-loop gain is not high) and low power consumption (just 20mA idle current at the O/P transistor !). If you are enjoying the music contents within Nait-2 list, you'll like it and keep using it for long years. It can't work for you for those louder American Country music (e.g. Thank God I am a Country Boy) nor Pop music (e.g. Bad, the Sad Cafe ) nor Big Symphony (e.g. 1812, Beethoven No. 5). My friend use it for years but I like the kind of music not on the Nait-2 list so I built a Class A 100W to listen to virtually all music or signal or noise.

7th December 2005, 03:55 AM	#10
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Hi etsang3, My... all those electros in the signal path AND the very ordinary topology with poor supply filtering and PSRR. No wonder it becomes easily confused on complex passages. Hi lokh, ...."Why do you want to modify the historical gem? " Gem.. hahahaha. Have to agree with last guy. Cheers, Greg

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