Nad 310 Amp

Marvellous · 8th August 2003, 05:41 PM

I have just gotten a Broken NAD 310 AMP From a friend
When I opened it I found that the BUZ555-60B
are Missing

So I went on to Check the rest of the Transistors (with a Multimeter) to find that all of them look fine

The PROBLEM is I can't find the BUZ555-60B anywhere if South Africa.
So is there onother component I can Substitute for the BUZ555-60B

or is there a way to tweaking the circuit to work with anothe Component?

I have never seen a Bipolar & FET output stage!

Pleeeese HELP!

Marvellous · 8th August 2003, 05:48 PM

Here the Amps Shcemetic!

http://steve.sky.net.ua/Audio/semi/A...p.gif:bigeyes:
Need Replacement of the BUZ555-60A

or Tweak to make amp work!
http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.gif

UrSv · 8th August 2003, 09:12 PM

You can substitute it with an ST type STP30NE06L according to:

http://www.repartout.com/Datasheets/...enceMOSFET.pdf

Marvellous · 9th August 2003, 08:19 PM

Thanks Help Much Apreciated!!!

Will Keep U Posted On Progress!!!

Marvellous · 9th August 2003, 08:30 PM

Opps I forgot here is the link to the Schemetic

http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.gif

Plese help!

Marvellous · 11th August 2003, 10:12 AM

STP30NE06L Can't Find That One Either!

Is There Any More You Guys Can Suggest

rmgvs · 13th August 2003, 09:00 AM

About 5 years back I owned a NAD 310. When I took the lid of the amp I was really surprised by what I saw. To begin with it is a amp with a asymmetrical power supply and a output-capacitor in the signal path. This was common practice in the sixties but never seen again since then (the Audio Innovations Alto is the only exception that I know of). Was this done deliberately?

Further I only saw one big transistor per channel upon the heat-sink, alongside a much smaller one. Could this be a single-ended transistor amplifier? No, because it is not working in class-A at all. And the brochure says the amp gives 80 Watts per channel at 2 Ohms: this would mean a massive standing current. But a push-pull amplifier with one big and one small transistor in the output stage?

I gave up understanding it because I had no schematics. Now I have the link for the schematics and will have a look at it (did not yet study it).

Has anyone looked at the schematics and formed an idea what the philosophy of this amp is?

Strange also the the brochure or any test that I read at the time do not mention the characteristics of the design.

Rudy

By the way: the amp did not sound very special to me. The old NAD 3020 (same price and still in my possession) was a better performer in my opinion. After listening to it for several weeks, I upgraded the power supply (bigger rectifier and caps) and gave the amp a higer bias current. It sounded better after that time.

Marvellous · 13th August 2003, 11:06 AM

Thanks UrSv & rmgvs for your help

Really Apreciate It!

I now think the Amp is not worth the Wake Up!

I have already built the P3A from Elliot Sound Products
and it Sounds Great!

so I can use it to amplify!

Question! again

Is there a way I can use the Pre-Amp of this Amp

where can I steel the Audio before it is fed into
the Power Amp Stage?

here the link to the pre Amp
http://steve.sky.net.ua/Audio/semi/Amp/NAD/310pre.gif

I was thinking just before R201 &202

Will This Work?

rmgvs · 13th August 2003, 12:59 PM

About using the preamp seperately:

If you unsolder the resistor R 201 from the circuit and take the signal from the wiper of the volume pot (where it is connected to the R201 resistor) you have your preamp.

In effect the output signal from the preamp is blocked by a electrolytic cap (47 mF) and goes straight to the volume pot.

Is not often seen that the pot is at the output of the preamp.

Now the output impedance is not a constant but depends on the position of the volume pot. Besides that the pot is of value 20k which is rather low for some applications. As long if you use very short cables (1 meter typically) between pre- and main-amp it looks that you got yourself a nice and cheap preamp.

Rudy

Marvellous · 14th August 2003, 07:17 AM

Quote:

Originally posted by rmgvs
About using the preamp seperately:

In effect the output signal from the preamp is blocked by a electrolytic cap (47 mF) and goes straight to the volume pot.

Is not often seen that the pot is at the output of the preamp.

Now the output impedance is not a constant but depends on the position of the volume pot. Besides that the pot is of value 20k which is rather low for some applications.
Rudy

Should I then Replace the POT(20K) to higher value?

it is going to be used as part of a Hifi system wich I'm Still building
what value should it Be?

when you say the output signal is blocked by a electrolytic cap
does that mean I have to bypass it?

If so which one is it (can you give me its number accoding to the schemetic)

Thanks for helping me out

Still Learning

8th August 2003, 05:41 PM	#1
Marvellous diyAudio Member Join Date: Aug 2003 Location: Gauteng	Nad 310 Amp I have just gotten a Broken NAD 310 AMP From a friend When I opened it I found that the BUZ555-60B are Missing So I went on to Check the rest of the Transistors (with a Multimeter) to find that all of them look fine The PROBLEM is I can't find the BUZ555-60B anywhere if South Africa. So is there onother component I can Substitute for the BUZ555-60B or is there a way to tweaking the circuit to work with anothe Component? I have never seen a Bipolar & FET output stage! Pleeeese HELP! __________________ "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute—and it’s longer than any hour. That’s relativity." - Albert E

8th August 2003, 05:48 PM	#2
Marvellous diyAudio Member Join Date: Aug 2003 Location: Gauteng	NAD 310Amp Here the Amps Shcemetic! http://steve.sky.net.ua/Audio/semi/A...p.gif:bigeyes: Need Replacement of the BUZ555-60A or Tweak to make amp work! http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.gif __________________ "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute—and it’s longer than any hour. That’s relativity." - Albert E

8th August 2003, 09:12 PM	#3
UrSv diyAudio Member Join Date: Jan 2002 Location: Sweden	You can substitute it with an ST type STP30NE06L according to: http://www.repartout.com/Datasheets/...enceMOSFET.pdf __________________ UrSv Those who say it can't be done should not stop those who are doing it.

9th August 2003, 08:19 PM	#4
Marvellous diyAudio Member Join Date: Aug 2003 Location: Gauteng	Thanks Help Much Apreciated!!! Will Keep U Posted On Progress!!! __________________ "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute—and it’s longer than any hour. That’s relativity." - Albert E

9th August 2003, 08:30 PM	#5
Marvellous diyAudio Member Join Date: Aug 2003 Location: Gauteng	Opps I forgot here is the link to the Schemetic http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.gif Plese help! __________________ "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute—and it’s longer than any hour. That’s relativity." - Albert E


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11th August 2003, 10:12 AM	#6
Marvellous diyAudio Member Join Date: Aug 2003 Location: Gauteng	STP30NE06L Can't Find That One Either! Is There Any More You Guys Can Suggest __________________ "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute—and it’s longer than any hour. That’s relativity." - Albert E

13th August 2003, 09:00 AM	#7
rmgvs diyAudio Member Join Date: Apr 2001 Location: Netherlands	hoe does it work? About 5 years back I owned a NAD 310. When I took the lid of the amp I was really surprised by what I saw. To begin with it is a amp with a asymmetrical power supply and a output-capacitor in the signal path. This was common practice in the sixties but never seen again since then (the Audio Innovations Alto is the only exception that I know of). Was this done deliberately? Further I only saw one big transistor per channel upon the heat-sink, alongside a much smaller one. Could this be a single-ended transistor amplifier? No, because it is not working in class-A at all. And the brochure says the amp gives 80 Watts per channel at 2 Ohms: this would mean a massive standing current. But a push-pull amplifier with one big and one small transistor in the output stage? I gave up understanding it because I had no schematics. Now I have the link for the schematics and will have a look at it (did not yet study it). Has anyone looked at the schematics and formed an idea what the philosophy of this amp is? Strange also the the brochure or any test that I read at the time do not mention the characteristics of the design. Rudy By the way: the amp did not sound very special to me. The old NAD 3020 (same price and still in my possession) was a better performer in my opinion. After listening to it for several weeks, I upgraded the power supply (bigger rectifier and caps) and gave the amp a higer bias current. It sounded better after that time.

13th August 2003, 11:06 AM	#8
Marvellous diyAudio Member Join Date: Aug 2003 Location: Gauteng	Thanks UrSv & rmgvs for your help Really Apreciate It! I now think the Amp is not worth the Wake Up! I have already built the P3A from Elliot Sound Products and it Sounds Great! so I can use it to amplify! Question! again Is there a way I can use the Pre-Amp of this Amp where can I steel the Audio before it is fed into the Power Amp Stage? here the link to the pre Amp http://steve.sky.net.ua/Audio/semi/Amp/NAD/310pre.gif I was thinking just before R201 &202 Will This Work? __________________ "When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute—and it’s longer than any hour. That’s relativity." - Albert E

13th August 2003, 12:59 PM	#9
rmgvs diyAudio Member Join Date: Apr 2001 Location: Netherlands	pre out About using the preamp seperately: If you unsolder the resistor R 201 from the circuit and take the signal from the wiper of the volume pot (where it is connected to the R201 resistor) you have your preamp. In effect the output signal from the preamp is blocked by a electrolytic cap (47 mF) and goes straight to the volume pot. Is not often seen that the pot is at the output of the preamp. Now the output impedance is not a constant but depends on the position of the volume pot. Besides that the pot is of value 20k which is rather low for some applications. As long if you use very short cables (1 meter typically) between pre- and main-amp it looks that you got yourself a nice and cheap preamp. Rudy

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