Fair enough. I think I have some banging around here.Input stage topology. The OPA134 is a JFET-input op amp while the LM4562 is BJT.
Who is that?
Not sure it's my place to put his name out there. But if you ask that same question on e2e.ti.com in the precision amplifiers forum, he'll probably answer you himself.
Admittedly I don't know what establishes an op amp as a classic though, does someone give us a plaque? Scott, did you get one for the AD797?
He did, albeit in the "oscillators" category 😀
He did, albeit in the "oscillators" category 😀
The LIGO guys were quite happy maybe you are less skilled in the art.
Even harder without critical listening and sonic memory.Life must be tough if you can't read the datasheet.
Even harder without critical listening and sonic memory.
I wasn't talking to you, I should have quoted. I was referring to the gentleman who seems to keep insisting the AD797 is an oscillator.
For guitar pedals maybe.
No, it depends on the gain you need.
I wasn't talking to you, I should have quoted. I was referring to the gentleman who seems to keep insisting the AD797 is an oscillator.

MM cart to 40db to 600 ohm RIAA to 20db.No, it depends on the gain you need.
I use the LT1358 now. Most of the number crunchers here think the slew rate is meaningless. I differ.
So I tried the LM4562 (one of the touted opamps on this thread). It couldn't resolve like the LT1358. So since there seems to be a cloud of test and measurement heavies here I throw out the request. I'm just seeing if anyone can come up with a better device since most here are quick to dismiss my 6 years of perfecting my design.
How about the OPA1612? It's not as fast ( 27v/uSec) as the LT1358, but it has better THD, noise, and CMRR specs.So I tried the LM4562 (one of the touted opamps on this thread). It couldn't resolve like the LT1358. So since there seems to be a cloud of test and measurement heavies here I throw out the request. I'm just seeing if anyone can come up with a better device since most here are quick to dismiss my 6 years of perfecting my design.
. I'm just seeing if anyone can come up with a better device since most here are quick to dismiss my 6 years of perfecting my design.
Outside audio this approach is not a valid one. Things like design, simulation and test are required. In the wacky world of hifi as long as you are not starving and you customers are happy then its the norm.
Here you go again, no let up, for all I know what you listen to would make me feel the same way. They have a lot of happy customers maybe they are all deaf idiots.
Actually several listening experiences of top end systems sent me out of the room I have no reason to believe yours would be any different.
You know, Scott, that's pretty strong stuff... but let's parse it out.
Yes, you don't know what my system sounds like.
That doesn't change the essence of what I said - namely that your brain learns to process the sound you have presented it with, more so over time, such that one "filters" out and past certain objectionable characteristics. This being a possible reason that your people did not hear what Adcom's people heard.
People buying Adcom being deaf and/or idiots? (what about people who buy Sony, or the like??)
No idea.
However, they may or may not know of or be able to hear, or afford gear without any sonic artifacts. The vast majority of people who buy audio gear, imo, probably do not have and have not heard or do not know how to assemble a "blameless" system (to borrow Self's term).
Frankly, this is why a lot of people who have and DO switch to tube gear do so - the sonic character is different than most solid state - it doesn't matter if one knows or thinks it is "less accurate" or not.
Your "top end" listening experiences?
Shows nothing definitive. Price is not a basis for judgement.
I agree a whole lot of fancy and expensive gear that I've heard is, can we say, less than impressive? Nah, let's say it sounds awful.
So, you've more or less deliberately avoided the key points of my post... which was about why you and your group were likely unable to pick up what the people from Adcom allegedly were hearing. Not sure why that is...
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Outside audio this approach is not a valid one. Things like design, simulation and test are required. In the wacky world of hifi as long as you are not starving and you customers are happy then its the norm.
Dear Bill,
Measurements are simply NOT predictive of how something will sound. Period.
THAT is why it is different.
IF you believe that measurements ARE predictive, then you'd need to specify your measurements, your parameters and their respective target levels. After that we could find out if in fact you get the results that you seem to think - namely that all units that are equal or better than the above specified elements do in fact sound indistinguishable from each other - is the case or not.
So, please state and specify, so that all reading can thereby simplify their (so-called) design process down to an objective and scientific process alone?
I presume that you are aware that there are many people who are tone deaf and do not know it? Also that people are color blind? People have "holes" in their hearing's frequency response (usually due to damage)?
Those people would have a much more difficult time perceiving certain things... the converse is that some people have perfect pitch, they are much MORE sensitive to pitch.
Connect the dots.
Now for a real perceptual problem with monolithic opamps.
When Fairchild started making transistors in the '60s the goal was to get the cost under a nickel apiece. With 50+ years of inflation that would be around a dollar apiece today. Even the costly AD797 has a per transistor cost much lower than that.
The only way to get the cost of circuits up is to use specialty parts like the Linear Systems FETs or rare old ones.
So common sense would indicate opamps are too cheap to be any good.
When Fairchild started making transistors in the '60s the goal was to get the cost under a nickel apiece. With 50+ years of inflation that would be around a dollar apiece today. Even the costly AD797 has a per transistor cost much lower than that.
The only way to get the cost of circuits up is to use specialty parts like the Linear Systems FETs or rare old ones.
So common sense would indicate opamps are too cheap to be any good.
Life must be tough if you can't read the datasheet.
It's even tougher when you can't read emoticons.
Dunno, what is a Neve 8078 worth per op-amp these days?
A lot?
Fwiw: " BA440's (discrete) and not BA640's (non-discrete)"
Having worked on the Neve boards, and having tested the opamp modules, I was and am not particularly impressed by the "performance".
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