Amazing opamp measurement shoot-out

[esl 63]

Is there any more good Op-Amp news?
Or is Samuel Groner the last Hero?
Samuel seems to be bussy in other projects (work...)
We have to respect that, but P L E A S E Samuel... if you read this, consider to do a follow up!!!

 

[tiefbassuebertr]

I miss measurements from dated and recent low cost op-amps like the 4558 or the LM833/LM837 in this study. I like low-cost good performers.

It's a great work otherwise, particularly because it shows the actual shape and spectrum of the distortion residuals. This is great information for anybody willing to interpret it.

I agree.
Unfortunately, I did not know this THD measuring report yet. There are a lot of threads here on diyaudio concerning comparisons of different op amps, but without any indication of this paper.

I sorely miss the correlation between measurements results and sound quality....

The fact, that there is shows the actual shape and spectrum of the distortion residuals, helps a bit.

Notice that Scott Wurcer is mentioned in the reference list:

[13] Scott Wurcer:
An Operational Amplifier Architecture with a Single Gain Stage and Distortion Cancellation
AES preprint No. 3231, March 1992

Along with such great men as
Douglas Self
Walter G. Jung

Where is the paper
An Operational Amplifier Architecture with a Single Gain Stage and Distortion Cancellation
([13] Scott Wurcer: AES preprint No. 3231, March 1992) online for download ?
Thank you very much for advices.
P.S.: In this case this paper is also of interest:
Evolution of High-Speed Operational Amplifier Architectures
https://pdfs.semanticscholar.org/f0b1/73d0f261554b3a7d73c370db303c27240c85.pdf

 

[jan.didden]

Scott's paper is about the design of the AD797 and well worth a read.
It is available from the AES library.

Jan

 

[tiefbassuebertr]

Carlos, I have answered you the best way that I can. I really don't have any absolute opinions on this subject.
The biggest problem with IC's, in my opinion, is that they tend to starve the output stage in order to save current, and this causes higher order distortion to be generated.
ALL my discrete preamp circuits operate in class A, and don't have this problem.

I also make this observation on different applications like RIAA head amps and line stages in pre-amplifiers.
Therefore I have started this thread (read post #12 and #1):
Discrete OP-Amp vs. Integrated OP-Amp include discret Buffer - e. g. AD797/844+IRF610
have you compare integrated op-amps include high current single ended buffer stage against completely discretes versions?
Thank you for a reply.

 

[jan.didden]

It's all a matter of perspective. Not many people here can design a discrete opamp with less than -100dB distortion. OTOH, ICs routinely go below -120dB with just a few mA of bias in the output stage.

It's never black and white.

Jan