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 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!
NAD 310Amp
Here the Amps Shcemetic!
http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.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
Here the Amps Shcemetic!
http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.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
You can substitute it with an ST type STP30NE06L according to:
http://www.repartout.com/Datasheets/Cross-referenceMOSFET.pdf
http://www.repartout.com/Datasheets/Cross-referenceMOSFET.pdf
Opps I forgot here is the link to the Schemetic
http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.gif
Plese help!
http://steve.sky.net.ua/Audio/semi/Amp/NAD/310amp.gif
Plese help!
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.
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.
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?
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?
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
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
Re: pre out
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
rmgvs said:
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
cap
The output cap is labelled C125/126. You can bypass it with something like 1 mF/MKT or MKP. You could even consider putting in 10 mF/MKT directly.
Better still is first try and listen. Changing caps not always leads to better subjective performance. Some electrolytics can be quite good (another option: try a black-gate of Silma Elnic and the like, these are electrolytics but they say they sound much better).
The volume-pot: just try. It also depends on the main-amp's characteristics if this works. Eventually, if you decide to replace it, you could change to a Alps 50k. Remember that with the pot at the output this matching problem will always be an issue.
Still another option: there are many good and simple preamp designs, you can use the enclosure, the input selector, the power supply etc etc around such a new and optimized design.
Rudy
The output cap is labelled C125/126. You can bypass it with something like 1 mF/MKT or MKP. You could even consider putting in 10 mF/MKT directly.
Better still is first try and listen. Changing caps not always leads to better subjective performance. Some electrolytics can be quite good (another option: try a black-gate of Silma Elnic and the like, these are electrolytics but they say they sound much better).
The volume-pot: just try. It also depends on the main-amp's characteristics if this works. Eventually, if you decide to replace it, you could change to a Alps 50k. Remember that with the pot at the output this matching problem will always be an issue.
Still another option: there are many good and simple preamp designs, you can use the enclosure, the input selector, the power supply etc etc around such a new and optimized design.
Rudy
Did try This and the Verdict IS
IS Does WORK! but it is NOT Satisfactory at all
Preamplifier works fine but the Resulting sound is not to a starndard I would like to achieve! Not that I am looking for state of the art but just something with nice sound!
So I have decided to keep the input selector and aproche making my own preamplifier
Are there circuits you can recomend?
Thanks for the time And Every thing! !
IS Does WORK! but it is NOT Satisfactory at all
Preamplifier works fine but the Resulting sound is not to a starndard I would like to achieve! Not that I am looking for state of the art but just something with nice sound!
So I have decided to keep the input selector and aproche making my own preamplifier
Are there circuits you can recomend?
Thanks for the time And Every thing!
!that bad?
Did not expect it to be that bad. The circuit looks reasonable on paper. I did test the preamp of the NAD 3020 on 'high end' main amps (tubes and class-A transistor amps) and after just a few minutes the conclusion is obvious: no match at all.
What are the alternatives? Just look at this site, the simplest is a preamp around a good opamp. I read a story of I think Mark Henessy around rebuilding the preamp of his musical fidelity A1. This preamp in itself is rather (very!) good (though also a deviating design, the pot is in the feedback loop resulting in crackling noises straight away) but his design is more logical and sounds the same. Look at google, search for A1 etc.
Another preamp that is attractive for his simplicity can be found at the pages of Nelson Pass. They are famous for their quality and ingenuity, and mutations of it can be bought at commercial prices in the shop.
It did not hear any of these designs so better listen to someone who did (please respond).
Of course you have to reckon with your existing power supply (around +50 Volts to start with, this gives many possiblilities though).
Rudy
Did not expect it to be that bad. The circuit looks reasonable on paper. I did test the preamp of the NAD 3020 on 'high end' main amps (tubes and class-A transistor amps) and after just a few minutes the conclusion is obvious: no match at all.
What are the alternatives? Just look at this site, the simplest is a preamp around a good opamp. I read a story of I think Mark Henessy around rebuilding the preamp of his musical fidelity A1. This preamp in itself is rather (very!) good (though also a deviating design, the pot is in the feedback loop resulting in crackling noises straight away) but his design is more logical and sounds the same. Look at google, search for A1 etc.
Another preamp that is attractive for his simplicity can be found at the pages of Nelson Pass. They are famous for their quality and ingenuity, and mutations of it can be bought at commercial prices in the shop.
It did not hear any of these designs so better listen to someone who did (please respond).
Of course you have to reckon with your existing power supply (around +50 Volts to start with, this gives many possiblilities though).
Rudy
Sorry if i'm asking an obvious question, but why don't you have the NAD repaired and sell it? Nothing in it is quite so good as to make the basis of a great preamp: certainly not the PS or the phono jacks or case. Or any of the other parts. Building one from scratch will give you a lot more flexibility and potential quality than basing it on the NAD remains.
everything new?
Analog_sa,
of course you are right.
Nevertheless this is a nice way of trying and building some circuits for a very reasonable amount of money. Besides that, the case of the NAD looks nice and you do no have to do a lot of drilling and other nasty stuff.
Just buying a new and nice case-work sets you apart a reasonable sum of money (more than a secondhand 310 will do in the market) and then you have to start buying all other components!
Rudy
Analog_sa,
of course you are right.
Nevertheless this is a nice way of trying and building some circuits for a very reasonable amount of money. Besides that, the case of the NAD looks nice and you do no have to do a lot of drilling and other nasty stuff.
Just buying a new and nice case-work sets you apart a reasonable sum of money (more than a secondhand 310 will do in the market) and then you have to start buying all other components!
Rudy
I couldn't get it repaired anywhere because of part availability here in SA! so it was going to cost me more than buying 2 5.1 surround Amps!
so Im busy building my pre Amp Inside the 310!
with a ESP surround Decoder!
for Amps
Dual P3A Amp Modules
and my own design a Stereo SoundBoy Amp!
Will Post Pics Soon!
so Im busy building my pre Amp Inside the 310!
with a ESP surround Decoder!
for Amps
Dual P3A Amp Modules
and my own design a Stereo SoundBoy Amp!
Will Post Pics Soon!
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