NAD 302 schematics wanted

kayes · 3rd July 2002, 05:50 AM

I have NAD 302 Amp and would like to tweak it as it contains ceramic caps and ofcourse plenty of space for tweaking like adding Caps for PSU/ Fast rectifiers/ PP cap bypassing. Can anybody out there help me with schamtics alone.

mhennessy · 3rd July 2002, 01:11 PM

Try looking here.

This site has schematics lots of stuff, including NAD310 and 312. I don't know how different the 302, but hopefully these might give you some clues...

Cheers,

Mark

acapulco · 1st April 2003, 07:28 PM

I tried the link but it is dead!
Any other tip where I can find NAD schematics.

Jay · 2nd April 2003, 03:25 PM

In my opinion NAD is one of a few companies that knows how to achieve great sound from cheap materials. I don’t know with ceramics caps, if it is the cheap green caps, I’m sure you cannot hear any difference if you replace it with first class MKP (or even MKT). Those caps are suitable for coupling capacitors (to ground) and in the DC rails near transistor pins. It is also very likely that the circuit has a zobel in the output, but there’s no need to put expensive cap here.

My NAD C320 uses massive PSU torroid and capacitance. The rectifiers are suspicious (because it’s cheap), but looking at the “complexity” of the regulator circuit as well as the complexity of the amplifier (multi stage amplification and feedback), I don’t think that replacing the rectifier worth the effort. In a simple circuit, component quality is more important to cover the drawback of a simple circuit. In a complex circuit, it is less so.

The HF section (of the tone control) uses cheap green caps, the LF section uses MKM. Isn’t that smart?

Jay · 2nd April 2003, 03:34 PM

And I thought that by removing the circuits for impedance sensing (ISC) and clipping would improve the sound. I didn't really compare the result, but I didn't find any miracles.

And I'm building 3-stage class A driver for the transistors. I mean, upgrading the whole circuit!

Tube_Dude · 2nd April 2003, 05:11 PM

The schematic of the output stage of the Nad 302 is tha same of the Nad 3020....only the devices (transistors) are more modern in the 302, but the topologie is the same...

Regards

joensd · 2nd April 2003, 05:47 PM

Mark, the given link doesn´t work for me likewise.
This should work : http://steve.sky.net.ua/a_index.htm

Cheers
Jens

mhennessy · 2nd April 2003, 07:00 PM

Quote:

Originally posted by joensd
Mark, the given link doesn´t work for me likewise.
This should work : http://steve.sky.net.ua/a_index.htm

Cheers
Jens

Hi Jens - thanks for correcting it...

Cheers,

Mark

acapulco · 3rd April 2003, 05:33 AM

Thanx a lot, it is really the same topolgy as 3020 ?? I will send this to poor guy in India he is trying to repair a NAD 302 so... it would be nice if it is fool proof.

Tube_Dude · 3rd April 2003, 02:28 PM

Quote:

Thanx a lot, it is really the same topolgy as 3020 ??

Yes it is...the output stage is the same only the devices are more modern...

Regards

3rd July 2002, 05:50 AM	#1
kayes diyAudio Member Join Date: Jun 2002 Location: Bangalore	NAD 302 schematics wanted I have NAD 302 Amp and would like to tweak it as it contains ceramic caps and ofcourse plenty of space for tweaking like adding Caps for PSU/ Fast rectifiers/ PP cap bypassing. Can anybody out there help me with schamtics alone.

1st April 2003, 07:28 PM	#3
acapulco diyAudio Member Join Date: Mar 2003 Location: Svalbard	NAD I tried the link but it is dead! Any other tip where I can find NAD schematics.

2nd April 2003, 05:11 PM	#6
Tube_Dude diyAudio Member Join Date: Mar 2002 Location: Aveiro-Portugal	The splendid Nad 302... The schematic of the output stage of the Nad 302 is tha same of the Nad 3020....only the devices (transistors) are more modern in the 302, but the topologie is the same... Regards __________________ Jorge

3rd April 2003, 05:33 AM	#9
acapulco diyAudio Member Join Date: Mar 2003 Location: Svalbard	NAD302 Thanx a lot, it is really the same topolgy as 3020 ?? I will send this to poor guy in India he is trying to repair a NAD 302 so... it would be nice if it is fool proof.

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3rd July 2002, 01:11 PM	#2
mhennessy diyAudio Member Join Date: Jun 2002 Location: UK	Try looking here. This site has schematics lots of stuff, including NAD310 and 312. I don't know how different the 302, but hopefully these might give you some clues... Cheers, Mark

2nd April 2003, 03:25 PM	#4
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	In my opinion NAD is one of a few companies that knows how to achieve great sound from cheap materials. I don’t know with ceramics caps, if it is the cheap green caps, I’m sure you cannot hear any difference if you replace it with first class MKP (or even MKT). Those caps are suitable for coupling capacitors (to ground) and in the DC rails near transistor pins. It is also very likely that the circuit has a zobel in the output, but there’s no need to put expensive cap here. My NAD C320 uses massive PSU torroid and capacitance. The rectifiers are suspicious (because it’s cheap), but looking at the “complexity” of the regulator circuit as well as the complexity of the amplifier (multi stage amplification and feedback), I don’t think that replacing the rectifier worth the effort. In a simple circuit, component quality is more important to cover the drawback of a simple circuit. In a complex circuit, it is less so. The HF section (of the tone control) uses cheap green caps, the LF section uses MKM. Isn’t that smart?

2nd April 2003, 03:34 PM	#5
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	And I thought that by removing the circuits for impedance sensing (ISC) and clipping would improve the sound. I didn't really compare the result, but I didn't find any miracles. And I'm building 3-stage class A driver for the transistors. I mean, upgrading the whole circuit!

2nd April 2003, 05:47 PM	#7
joensd diyAudio Member Join Date: Dec 2001 Location: Germany	Mark, the given link doesn´t work for me likewise. This should work : http://steve.sky.net.ua/a_index.htm Cheers Jens

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