Someone tell me how to delete this thread from my getting the messages? It is clear we have those who just won't believe in science beyond their personal beliefs, T&M is only applicable outside of audio, what a bunch of BS! I think there is some very delusional thinking going on here. Golden eared audiophiles, might as well just go by the selections that Stereophile gives, just as good information as being bandied about here, totally ignorant as far as I can tell. Go get your silver platted copper wires, have at it!
Oh c'mon Scott, it was addressed at Mesrs. Jung, Didden and the Superregulator....
But if you want to trade barbs, I can mention a certain mic pre where oscillations happened with a lesser opamp. Albeit that would be unfair since you eventually managed to contain them. Mesr. Jung blamed the part ("RF pickup" tee hee).
Who said that T&M is only applicable outside of audio?
Quote it.
You're frankly making up things.
IF you think that T&M is predictive of what sound comes out, please STATE in unequivocal terms what the T&M STANDARD needs to be. Or even approximate where you expect those numbers to be.
You won't. Because you can not.
Either everything is the SAME in terms of sound or it is not.
IF it is not, then there must be some difference(s).
IF those differences can be fully specified and described by T&M, then there by definition will be some "GO/NO GO" threshold(s).
STATE THEM.
Bear, Scott can't hear what you hear. He never could and he never will. The arguments you are making may be true, but they are not going to ever be convincing to him. If you want him to consider changing his mind, you will need to show him some well-conducted research in support of your position. To do that would take time, effort, money, specialized test equipment, and so on. Otherwise, you two will continue to disagree. Probably not of any practical use to keep talking past each other.
Bill - the contention here is not about the necessity of Measurement. It's about whether you can skip Design.
Morinix, did you OPA134 or not? I'm curious of your impressions. And no I won't ask for ABX THD or anything. You can even PM me as to keep out the numerologists from the discussion.
But you can certainly tell him that a few guys here are very appreciative of his design. More so as I think that he didn't target audio initially? It was an aftertought after noticing that OPA132 works so well for such? Or was it the other way round?
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Here's an outfit making well specified discrete opamp "retrofits"/upgrades for pro audio application...
look around... different versions.
they say class A outputs...
can't upload, the files are too big... 🙁
Model 992Enh Discrete OpAmp
look around... different versions.
they say class A outputs...
can't upload, the files are too big... 🙁
Model 992Enh Discrete OpAmp
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The bipolar ones look like the JE990, inductors across the input stage degeneration. The FET one specs min Ib 400pA max Ib 600pA which makes no sense at all. Forsell makes stuff like this too. 20V/us and lots of zeros in all the THD graphs.
All this minutia talk about opamps, BFD.... Just by putting different mixtures on the AM loop antenna of my shelf consumer-fi sound source I can profoundly change the sound and timbre of my system, who cares about what's downstream, guys get with the program.
THD really does not matter.
Dan.
THD really does not matter.
Dan.
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Yes, let us listen to a man who claims to be able to copy WAV files from device to device and permanently alter the way they sound without altering the data. 🙄
They do make a 990 clone "upgrade" - I think the other ones are derivative of later Hardy offerings, or others similar designs.
There may or may not be typos in the spec sheet, dunno.
You could always inquire...
but that's somewhat beside the point... I offered it as a contrast to the NEVE "standard" opamp, and wrt the earlier mentions of doing "the same thing" in discrete. While drawing no conclusions.
EDIT: apparently Dick Burwin predated the Deane Jensen use of the inductors - but I do think it is a very clever thing to do.
If you change the Q of an AM loop antenna then you may change the audio bandwidth. This may be audible, given a good quality transmission (I guess these might exist somewhere in the world). Not sure what this has to do with this thread.Max Headroom said:
Listen to 30% THD. You might find it matters to some extent.
I have the sudden urge to hum 'Pyramania' (Alan Parsons Project.)
Yes I like Prog. Doesn't make me any more Evil than you already thought I was 😛
Yes I like Prog. Doesn't make me any more Evil than you already thought I was 😛
Changing the Q of a typical AM ferrite loop antenna will have no effect on the received bandwidth.
Forget 30%, given the T&M data/tests/papers, at what "THD" does "THD" become audible? And, at what level does it become inaudible? You know, the hysteresis around the absolute value of Go/No Go??
Still curious about this...
_-_-
That makes interesting reading 🙂 😎
What would be achieved if they could shrink it onto a silicon die and put it into a surface mount package? Probably a great deal. It would have to compete with an existing $0.50 item that gives 90% of the performance and almost immeasurable loss in quality though 🙁
I imagine a valve based 8 pin replacement would take some work. Steampunk engineering.
My imagination is now flowing: New steam-powered Vauxhall Astra: Does 50 miles per bag of coal, only require servicing (ash removal) every 500 miles and uses as little as 20 gallons of water per bag of coal.
The diesel version costs £5,000 dollars less, but you don't get the warm glow, pseudo eco friendly aura and admiring glances from men in white coats 😱
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I AM interested in this thread and the varied opinions. Discrete OP-Amps? I never realised and it makes genuinely interesting reading.
This website has a pragmatic approach to op-amp selection.
NwAvGuy: Op Amp Measurements
This website has a pragmatic approach to op-amp selection.
NwAvGuy: Op Amp Measurements
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