Just a comment, this gets a little close to the line sometimes. I am here pro se and can not answer (especially now) for any policies. BTW I would take any claims for Bob Pease's opinions with a grain of salt. In private he was not very sympathetic to the audiophile cause, though he saved his worst for things like the "Taguchi Method".
Sounds better, yawn. I doubt the protocal would pass muster.
I suspect the current noise is his problem not the voltage noise. The 2nV input voltage noise would never show up until huge closed-loop gains. There never was a guaranteed noise spec. so you were always on your own.
You do know how to analyze the noise performance of CFA's I assume? '-).
EDIT Congrats John seems they've taken you off moderation. I meant listening protocol, it really is tedious, I suspect they went to someone's basement and had a few beers while op-amp rolling.
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"The noise spec. is 2nV/rt Hz typical. There is NO worst case spec. So I guess they can sell 'trash' at full price, and get away for it. '"!
John, I am shocked that you comment this way!
No professional designer relies on Typical (which means not individually tested or guaranteed) specs, especially if that is critical to the design!
OK to select out parts for specific jobs, but this CANNOT be relied on for long term production! I cannot believe you think this way and blame the manufacturer for your own lack of professional integrity.
John, I am shocked that you comment this way!
No professional designer relies on Typical (which means not individually tested or guaranteed) specs, especially if that is critical to the design!
OK to select out parts for specific jobs, but this CANNOT be relied on for long term production! I cannot believe you think this way and blame the manufacturer for your own lack of professional integrity.
If the issue is the lack of easy feedforward correction there may be another approach.
For those who would like the basics: http://www.google.com/url?sa=t&rct=...05r4nMd0CrchaOYLdN233cg&bvm=bv.53371865,d.aWM
For an external approach:http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=SNOA646&fileType=pdf
Neither quite gets you there, but they are a start at another approach.
Now as to a typical noise spec, there is no guarantee, HOWEVER if you are measuring batches and the average is above the typical then you should have a lever.
For those who would like the basics: http://www.google.com/url?sa=t&rct=...05r4nMd0CrchaOYLdN233cg&bvm=bv.53371865,d.aWM
For an external approach:http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=SNOA646&fileType=pdf
Neither quite gets you there, but they are a start at another approach.
Now as to a typical noise spec, there is no guarantee, HOWEVER if you are measuring batches and the average is above the typical then you should have a lever.
Integrity is too strong a word, I would say judgement. It is true that issue was one of Bob Pease's hobby horses, if you want a typ. specification guaranteed expect to pay for it and expect due to scale of business to sometimes get no for an answer.
Scott, this sort of reminds me of when SY had a problem with a VW engine and he got perhaps 1/2 the expected miles, and was given no compensation from the factory. How dare he complain! They only 'guaranteed' a few years and a lower mileage. ;-( I still feel a bit sorry for SY, though, and I TOO would complain about it. Buy a Porsche next time, SY! '-)
My Saab threw a rod and scored all the pistons at 50,600 miles on a 50,000 mile warranty. The factory did a full short block replacement for free, a three page bill with 0 balance at the end.
EDIT It actually was 50666 miles but I thought no one would believe me.
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Perhaps SY has a heavy foot?
LMAO - I swear my son red lined the car the day before driving us home in too much of a hurry.
As usual, a complete fabrication. Try telling the truth, it's easier. (In warranty, as I clearly said. Not as good for you to make a phony point.)
So although you wouldn't give a direct answer, can we infer that your design relied on an unspecified parameter?
Are you calling me a liar, again, SY? Why? What did I say now? I took what I THOUGHT you said, several days ago. Perhaps I read it wrong. Are you telling me that the VW engine WAS under warranty, and that you got compensated for your problem? A, OK! Then why were you griping about it?
That is sort of where Charles was when he tested the ADI parts and tried to return the defective ones. He didn't complain much about that, it was ONLY when they REFUSED to replace the noisy parts. See the problem?
That is sort of where Charles was when he tested the ADI parts and tried to return the defective ones. He didn't complain much about that, it was ONLY when they REFUSED to replace the noisy parts. See the problem?
JN, have you PRICED these parts? OF COURSE, they met the criterion that they worked as an amplifier. BUT, they DID SPEC. the noise, and they maintained it for a decade or so.
No, ADI is not alone on this.
Back in 1973, with a QuanTech, I found the Siliconix J110 to be very quiet, and I used it for the first stage of the phono gain block for about 3 years. THEN, Siliconix changed the process and NONE of the J110 parts met spec. and we had to find something else. Of COURSE, they did NOT remove the noise graph from the jfet handbook that looked so good, that Ed Oxner and I 'generated' from the QuanTech measurements. Why bother the engineers with not meeting what they used to meet? These devices were analog SWITCHES not analog amplifiers. And so it went, back in 1976. Thank goodness, Toshiba came through in 1978 with the 2SK146.
No, ADI is not alone on this.
Back in 1973, with a QuanTech, I found the Siliconix J110 to be very quiet, and I used it for the first stage of the phono gain block for about 3 years. THEN, Siliconix changed the process and NONE of the J110 parts met spec. and we had to find something else. Of COURSE, they did NOT remove the noise graph from the jfet handbook that looked so good, that Ed Oxner and I 'generated' from the QuanTech measurements. Why bother the engineers with not meeting what they used to meet? These devices were analog SWITCHES not analog amplifiers. And so it went, back in 1976. Thank goodness, Toshiba came through in 1978 with the 2SK146.
That seems to be a suspiciously recurring theme.
Yes, the problem is that you're making stuff up again, since I didn't say that, either; in fact I said exactly the opposite. But if a fabrication helps you defend a poor engineering practice, go for it.
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