NE5532P bipolarny, oldschoolowy
OPA1656 nowoczesny J-FET
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Sparkos SS3602 Opamp Rolling In Fosi P4
- Thread starter amirm
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OPA1656 nowoczesny J-FET
I'd be lying if I said I didn't like the 1656 opamp. I do. I've designed circuits for it and it's excellent! High value. Problem is, it's a spitfire. You just can't throw this thoroughbred in circuits willy nilly and not have it function as an oscillator once in a while.
solderdude
Grand Contributor
PCB layout and local power rail decoupling... that's what that is all about.
Probably true, But when @Ggr used the word "difference" I'm pretty certain he meant "improvement". Not : "Completely buggered up by instability"
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Sincerely, you have been gaslighting. The nitpicking and FUD-casting on other people's measurements and data. Jumping from topic to topic to keep from having to account for the things you are claiming. Misinterpreting. Not answering direct questions. Appeals to authority, and elitism. You seem to think you have unique access to stuff and experiences, which is odd given the forum you are posting at. For example, I have a box full of your unicorn OPA627. Let's check them out.
But first, briefly return to an example earlier in the thread, the OPA2604, and establish a baseline for distortion performance before I shoehorn some OPA627 into the preamp I have been using here.
I loaded pairs of NE5532, OP275, TL072, OPA2227, OPA2228, LM4562, OPA2604, OP270, OPA2132, OPA2134, and LF412C into the preamp. I swept the output to clipping. re are THD+N and THD for the group. I zoom in on THD to get a better view.
The NE5532 and a handful of OpAmps all stand out with best distortion performance in this application. The OPA2134 is among the best for distortion, which is great since I also have the OPA134, and I can make single- to dual-OpAmp adapters made two adapters since my preamp has two gain stages. The adapters prevented me from closing the lid on the preamp. But I see lots of OpAmp rollers who can no longer close lids on their gear.Cut holes.
Etc. So I'm fine.
To establish a baseline between the OPA2134 performance and the OPA134 mounted on my adapters, I did four runs. I did a run with all OPA2134 in the preamp, a pair of runs with just one OPA134 adapter configured with an OPA2134, and a run with both OpAmps using the OPA134 adapters. All of these are line on line matched for distortion, which I measured since you would have cast doubt on the validity of the result since my adapters are crude, not made from exotic materials.
View attachment 471903
I get the same results with the OPA134 as the OPA2134. Let's compare the OPA627!
Next, I measure the OPA627 across output voltage. The OPA627 has slightly lower distortion at 2-4V.
View attachment 471906
This is great performance, the differences are tiny, not audible.
To me you are wrong al 10mV thd is -80db and 100mV 95db the THD is audible , the yellow one in the first pic have lot thd then all othersSincerely, you have been gaslighting. The nitpicking and FUD-casting on other people's measurements and data. Jumping from topic to topic to keep from having to account for the things you are claiming. Misinterpreting. Not answering direct questions. Appeals to authority, and elitism. You seem to think you have unique access to stuff and experiences, which is odd given the forum you are posting at. For example, I have a box full of your unicorn OPA627. Let's check them out.
But first, briefly return to an example earlier in the thread, the OPA2604, and establish a baseline for distortion performance before I shoehorn some OPA627 into the preamp I have been using here.
I loaded pairs of NE5532, OP275, TL072, OPA2227, OPA2228, LM4562, OPA2604, OP270, OPA2132, OPA2134, and LF412C into the preamp. I swept the output to clipping. Here are THD+N and THD for the group. I zoom in on THD to get a better view.
View attachment 471896
The NE5532 and a handful of OpAmps all stand out with best distortion performance in this application. The OPA2134 is among the best for distortion, which is great since I also have the OPA134, and I can make single- to dual-OpAmp adapters.
I made two adapters since my preamp has two gain stages. The adapters prevented me from closing the lid on the preamp. But I see lots of OpAmp rollers who can no longer close lids on their gear.
To establish a baseline between the OPA2134 performance and the OPA134 mounted on my adapters, I did four runs. I did a run with all OPA2134 in the preamp, a pair of runs with just one OPA134 adapter configured with an OPA2134, and a run with both OpAmps using the OPA134 adapters. All of these are line on line matched for distortion, which I measured since you would have cast doubt on the validity of the result since my adapters are crude, not made from exotic materials.
View attachment 471903
I get the same results with the OPA134 as the OPA2134. Let's compare the OPA627!
Next, I measure the OPA627 across output voltage. The OPA627 has slightly lower distortion at 2-4V.
View attachment 471906
This is great performance, the differences are tiny, not audible.
Here are OPA627 compared to OPA134 at 2V output.
Hey, since you were speculating, what other physical property determines how sound is reproduced?
RandomEar
Major Contributor
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Most people fail to detect distortion below -40 dB in real music even under ideal test conditions with quick switching and their best foot forward. With pure tones and using headphones, some lucky listeners reach a bit below -50 dB. Test it yourself.
-95 dB is literally the limit of audio CDs. If you think you can detect audible distortion which was not part of the original recording in correctly mastered 16 bit 44.1 kHz material, please share your ABX results supporting that idea.
not a serius responce sorry
RandomEar
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Objective evidence and showing the ability to even verfiy it yourself is "not a serious response"?
solderdude
Grand Contributor
What it shows is a 6dB higher noise level, not higher distortion which is similar (and for higher frequencies even better) than OP2227.
It is still is below audible levels as the noise that is measured is likely well above the audible bandwidth.
Most likely caused by its higher bandwidth.
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please look thd at 20>>100mV is not the same thd at 2V ....
when the power out goes down an thd goes up we have a problem !
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solderdude
Grand Contributor
Actually the distortion goes down.
What you see is the S/N ratio getting worse as the signal is lower and noise stays the same.
Also look at the ranges (left scale).
It seems worse than it is due to (auto?)scaling.
What you see is the S/N ratio getting worse as the signal is lower and noise stays the same.
Also look at the ranges (left scale).
It seems worse than it is due to (auto?)scaling.
maybe, can be crossover or loop gain
solderdude
Grand Contributor
NO, as I explained.
S/N ratio.|
It just looks bad because of the scaling.
S/N ratio.|
It just looks bad because of the scaling.
There is no crossover distortion in a not substantially loaded op-amp (they are class-A with loads > 2kohm)
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if you do not look under never know
solderdude
Grand Contributor
What do you mean with this ?
