Amazing opamp measurement shoot-out

[forr]

Hi QSerraTico_Tico,
---Then may I ask what is the use of these measurements for audiophiles?---

May I answer that some audiophiles prefer very low noise and distorsion circuits ?

[KSTR]

NJM4580==RC4580 (or at least very very close, looking at the spec).

RC4580 is on page 194.

[john curl]

These measurements mean a lot to me. In fact, I learned plenty already from this paper. Is it EVERYTHING that I need to know? NO. But it is useful and helpful in evaluating IC op amps. I am now releasing an all IC op amp phono stage. It is important to know subtle things about each IC, (like non-linear input stage impedance) leading to distortion.

[destroyer X]

Thanks in advance to loose some time to answer me.

For sure this data serves to select the better one to use.

I have an advanced question before select them to use... are they better than discrete equivalent simplified circuit when listened by normal, common humans?.... this is in advance to go selecting them to use watching data sheet.

Some numbers are helpfull, alike to select a wife because so tall as we are, to produce tall sons maybe...or at least not so different than your family.... good selection...but this is just one thing..marriage has thousands of factors to allow us to make a good decision... those numbers, data sheet, are alike to select wife because 6 feet high alike me...but the other more important subjects we cannot know about her... also about sonics...only distortions and measurements can't tell us the whole story.... there are some low distortion amplifiers that sounds terrible...and also there are some distorted samples really interesting.

Electronic Tubes (Valvulas) sounds great and do not measure fine.

Your answer is very important as you are a very respectable man into our communitty.... if you say they can sound better, that you have experienced that, even ONCE...i will start to use them, to search for the better one.

I have a good friend, Rabbitz, that already told me they can be good as pré amplifier to LM4780... this is something to try and explore..so.. i will assemble and test some OPA with this chip amplifier.

Of course first reason to be married is the passion, the illusion of love... this feeling is important too...to love those chips...to feel them interesting...so...there are other factors, some human feelings into the equation.... the "belief" is one of them.

I have a friend with the most ugly woman you can watch in this world...the woman is worse than a dragon drunk that has crashed against a mountain... he "belief" she is wonderfull and intelligent... when nor one nor other..but he is HAPPY with that belief.... this is crazy...but we are humans and we have human perception too... some folks perceive loud and distorted as good sound.

It is hard to ask people things alike i am asking...people has not courage to answer and have not competence (skilled enougth, know how enougth, live expertise enougth...experience enougth)..... reason why, i am directly asking John Curl directly.

I hope you are not "connected" having good friends into chip amplifier factories or something political problem to tell me things frankly..... please... will keep secret and write to me your evaluation directly if needed... secrecy guaranteed.... and post the political scape here.

panzertoo@yahoo.com

regards,

Carlos

[mlloyd1]

i think the measurements help provide feedback on the quality of the design/designer: for example, were 2nd, 3rd, etc. order effects considered and addressed, etc.
this data can help weed out parts that may not be worth your time to consider for a particular application or point you towards parts that you may want to focus your attention on.

Originally posted by QSerraTico_Tico
Then may I ask what is the use of these measurements for audiophiles?

[scott wurcer]

Originally posted by john curl
These measurements mean a lot to me. In fact, I learned plenty already from this paper. Is it EVERYTHING that I need to know? NO. But it is useful and helpful in evaluating IC op amps. I am now releasing an all IC op amp phono stage. It is important to know subtle things about each IC, (like non-linear input stage impedance) leading to distortion.

Not too shabby for an 18yr old design, don't ya think?

[john curl]

Not bad Scott, but I do see some higher order, and I still want to offset output bias with a fet in order to reduce it. What is it with this high impedance drive distortion? I have to look at that more closely. I have been comparing the 797 with the 1115 and you are winning so far, except for price.
What really gets me down is when a low noise op amp can't drive a reasonable value feedback resistor without a lot of extra distortion.
Also, Scott, you should check out the low noise instrument thread and give them some help. Just look at the input stage and you will understand. I think that the feedback should come from the IC designer, for best effect.

[destroyer X]

This answers everything.

Political commitments require some care about comments posted into free, open International forum, in special when people is famous and must be carefull when open the mouth to comment about those things... providing evaluations and diagnosis.

To me it seems that these things, the use Ics instead of discrete, are just fashion generated by the pressure of the technological moment, the use of modern things, or what is more appropriate and politically correct, in obedience to the groups that generate opinions ... then, I think, in the case, possibly some solutions are adapted to market needs .... then, very probably, is whether what is needed, not what is objectively and subjectively the best solution ... but what is more easily accepted as good or better.

The silence, in some cases, is eloquent

Thank you not to answer directly or using mail Mr. John Curl, as gave me a lot of informations... silence seems a lot to me.... in special that has a lot of respect on me.

thanks,

I will continue with my beliefs.

Carlos

[lineup]

Originally posted by destroyer X:
I have a friend with the most ugly woman you can watch in this world...the woman is worse than a dragon drunk that has crashed against a mountain... he "belief" she is wonderfull and intelligent... when nor one nor other..but he is HAPPY with that belief.... this is crazy...but we are humans and we have human perception too...


This is a wellknown fact.
You often see the most 'beautiful' woman (on the outside)
having some real unpleasant, short and fat, old and ugly man.
And be quite happy with this 'animal' at her side ....
Lineup


This following is one clever polemic & protest song, to
The Cult of being YOUNG & BEAUTIFUL .. at any price (even facelifts!)
Originally posted by Bob Dylan 1987 in an album I have in my collection:

The woman that I love she got a hook in her nose
her eyebrows meet, she wears second hand clothes
She speaks with a stutter and she walks with a hop
I don't know why I love her but I just can't stop

You know I love her
Yeah I love her
I'm in love with the Ugliest Girl in the World

If I ever lose her I will go insane
I go half crazy when she calls my name
When she says babababababy I l-l-love you
There ain't nothing in the world that I wouldn't do

You know I love her
Yeah I love her
I'm in love with the Ugliest Girl in the World

The woman that I love she got two flat feet
Her knees knock together walking down the street
She cracks her knuckles and she snores in bed
She ain't much to look at but like I said

You know I love her
Yeah I love her
I'm in love with the Ugliest Girl in the World

I don't mean to say that she got nothing goin'
She got a weird sense of humor that's all her own
When I get low she sets me on my feet
Got a five inch smile but her breath is sweet

You know I love her
Yeah I love her
I'm in love with the Ugliest Girl in the World

The woman that I love she a got a prizefighter nose
Cauliflower ears and a run in her hose
She speaks with a stutter and she walks with a hop
I don't know why I love her but I just can't stop

Copyright ©1987 Special Rider Music

BobDylan.com - Ugliest Girl


also, do not forget the old halojoy topic
an intelligent twist using same message ....
UGLY Looking Amp! - but good working

halojoy, February 2003:

Of natural causes, it is only the most "beautiful amps"
that get pictures posted. They are running the SHOW.
But surely they are only "the tip of an iceberg".

95% of All Good Great Sounding DIY-amps are REALLY Ugly.

[john curl]

Carlos, you have no right to commit me to an opinion about IC's vs discrete. I design with both, and discrete is almost always better. It is also more complicated and expensive. I first started testing linear IC's 42 years ago, and I have devices from that time and many hundred types in my lab as samples or for production. This 'op amp shoot-out' helps me by saving me the time and effort to make similar measurements, myself. Virtually ALL the op amps that I am now using for audio are listed in this paper.
Actually tubes would most probably have lower input resistance distortion that is in many IC's, but I don't have enough room for tubes with this design.