Nelson Pass discrete op-amp.

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Upupa Epops said:
Fig 8 is princip of simplest discrete opamp. What are you waiting ? Go to to the nearest patent office and there you can find thousands of examples ( better ) circuits. :cool:

Dear Mr. Upupa,

Thank you very much for your kind reply.
Actually I am looking for a simple circuit with a minimum of active components (3 max) suitable for a nice line preamp.
I have already posted one with just two BJTs.

I would be very grateful if you could give me some info about similar minimalist line preamp (possibly schematics eh, eh).

Kind regards,

beppe61
 
Upupa Epops said:
Why only 3 components ? 3 components are 3 components and you can't wait miracles, although it is written by Mr. Pass. If you can make very good discrete amp ( only little bit complicated ), look at pages of Borbelly Audio. :cool:

Dear Mr. Upupa,

Thank you very much for the valuable suggestion.
I guess it is possible to obtain nice results with simple topologies like in the case of Pass Aleph P and L preamps for instance.
I must also confess you that I am not so good at DIY.
So I hope to have less difficulties in implementing simpler circuits.
I don't think that good results imply complexity on principle.
My approach is becoming a little "ZEN" if I can say that.
Simple but good and effective.
Few good components used in their best working conditions.
May be I am completely wrong.
Don't know really.

Kind regards,

beppe61
 
I think that Mr Pass (and others) wrote great articles, have an excellent knowledge, but some people misunderstand the concept.

The "keep it simple" principle is something beautifull, but making a good sounding and working product out of a simple topology is really an art. Everything simple isn't perfect, far from that. Many people misunderstand the concept, and think that every simple topology works better than every complicated one. That's untrue. Otherwise, no company would produce amps with more than 3 parts, is 3 parts would sound better and cost much less.
 
Upupa Epops said:
Dear beppe, blind faith to apostle of simplicity NP is good think, but exist also others apostles. For me is it Erno Borbelly and Walt Jung. Maybe, when you will read other " holy " book, you will change your opinion.

Dear Upupa,

Thank you again for your valuable suggestion.
As I can see you are Erno Borbely "supporter", do you remember his two fet line buffers ?
I will try to rescue the schematics and I will upload them.
What do you think of them?
They had +/- 24V dual power supply.
He wrote that they are very good to drive a power amp.

I look forward to hearing from you.

Kind regards,

beppe61
 
Bricolo said:
I think that Mr Pass (and others) wrote great articles, have an excellent knowledge, but some people misunderstand the concept.

The "keep it simple" principle is something beautifull, but making a good sounding and working product out of a simple topology is really an art. Everything simple isn't perfect, far from that. Many people misunderstand the concept, and think that every simple topology works better than every complicated one. That's untrue. Otherwise, no company would produce amps with more than 3 parts, is 3 parts would sound better and cost much less.


Dear Mr. Bricolo,


I think that audio market (like every other business) is only marketing driven by now.
Do you think that a very beautiful front panel of 1 cm is needed for a good sound?
I don't think so.
The front panel is there to give to justify a big retail price.
There are so many examples of very simple preamp and amps that got the consensus of audio lovers.
Just look at the AKSA amps for instance.
If you want my opinion I strongly think that sometimes equipments are unecessary complex.

Kind regards,

beppe61
 
To Bricolo : I have no doubt about deep knowledges of Nelson Pass :cool: , many times I had read his inspirating notices. But many times I had listen distortion coming from his amps, which lead me to the convicion, that all is good promotioned joke ;) . People easy take easy solutions, but it is not my case. I understand to this concept, but I don't agrre.
 
Upupa Epops said:
To Bricolo : I have no doubt about deep knowledges of Nelson Pass :cool: , many times I had read his inspirating notices. But many times I had listen distortion coming from his amps, which lead me to the convicion, that all is good promotioned joke ;) . People easy take easy solutions, but it is not my case. I understand to this concept, but I don't agrre.


Dear Upupa,


I forgot to ask you on what do you base your judgements about audio equipments: listening tests or measurements?
In either case I would be very interested if you could give some more details (i.e. how do you perform listening tests or what do you measured).

Thank you very much indeed.

Kind regards,

beppe61
 
beppe61 said:
...Actually I am looking for a simple circuit with a minimum of active components (3 max) suitable for a nice line preamp.
I have already posted one with just two BJTs.


Hi beppe61,


Have you built the two BJTs line preamp you posted?
I'm very interesting in knowing how does it sound...

I agree with your opinions that simpler can be better.
Specially in audio design, simpler means less degeneration to
the signal, and less degeneration means better quality.

This is why I always prefer discrete design than a monotholic
opamp.
Monotholic opamps always have dozens of parts in them
and they are intended as a universal devices. A discrete design
for a certain purpose will be simpler and will sound much better.


Regards,

Udi.

Albert Einstein said:
 
udip said:



Hi beppe61,


Have you built the two BJTs line preamp you posted?
I'm very interesting in knowing how does it sound...

I agree with your opinions that simpler can be better.
Specially in audio design, simpler means less degeneration to
the signal, and less degeneration means better quality.

This is why I always prefer discrete design than a monotholic
opamp.
Monotholic opamps always have dozens of parts in them
and they are intended as a universal devices. A discrete design
for a certain purpose will be simpler and will sound much better.


Regards,

Udi.

Albert Einstein said:


Dear Udip,

I built it.
I think it sound very good but may be I am only me that I hear things. I am not a very experienced audio listener.
That is the point.
I posted this very simple line preamp schematic (a part of a commercial old but well reviewed preamp of the mid '70s) to stimulate someone with much more knowledge and experience of audio equipment here to build it and to report his opinion.
For the 60V power supply I used the schematic of the one proposed in the article of the Bride of Zen preamp from Nelson Pass.
I think about this: every amplification stage adds distortion and we rely on feedback to cancel it.
Is this process without drawbacks?
My answer: I REALLY DON'T KNOW.

I look forward to hearing from anyone willing to build another one.

Kind regards,

beppe61
 
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