Neither can I with you, considering your priceless zero contribution in 215 posts over 12 years of DIYAudio membership. Call me when you decide to share other things than unsubstantiated opinions. Or not.
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What is a "dual op amp reg"? You mean "buffer"? I certainly doubt that, since I don't see in the ESS reference board the ES9311 being fed from a low noise power supply, but straight from the +5V board supply. As you certainly realize, the op amp buffer won't itself filter the noise, other than on the input RC cell. At 20dB/decade for a single pole LPF, that's pretty much nothing.
That's because this project is not for audio reproduction, but for instrumentation purposes. As such, it has to be better (distortions, noise, etc...) than anything that can be built today, at audio frequencies. In fact, my not so secret goal is to beat hands down the APx555 hardware performance. I already tried an analog loop between this ES9038PRO board and the ADS127L01 ADC and it is overall 3-6dB better than the APx555 spec (I can measure down to -140dB on the digital side), however the hard part is still to come: I/O stages, autoranging, I/O protections, etc... And all I can hope is to connect to a PC with e.g. ARTA, since I am not about to spend the rest of my life in writing software for this instrument. I have to admit, for the moment all I have is an expensive super sound card, and the performance margins for adding the required circuitry to make this a calibrated instrument are very, very tight. Not even sure if I will ever succeed.
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You may need an immersion in the NA life style. Unless one is in the academia, or in an otherwise formal environment, "stinkin'" "effing", "motherf...", etc... are used here more than you would, as a refined European, enjoy, and not necessary for denoting an action or for being taken stricto sensu. Much more used than your familiar "scheisse". I am fluent in German, BTW, and of European origins, I lived for many years on both sides of the big pond.
And somehow, I don't think there's a 4 years old audience here that need to be spared some language. What other thing about the "tone" importance is not something high on my list of concerns.
By dual I mean two outputs. You do realize that a voltage regulator in principle is nothing more than a reference being buffered? So whats the difference between a opamp buffered voltage reference versus a voltage regulator??? Both use negative feedback, the more the better, to make the reg output follow the input (the reference) as closely as possible...
What I meant to say is that the ES9311 internal structure is probably very similar to a reference buffered by opamps. that IS speculation though.
What are you planning to do with your super soundcard? What are you planning to measure? What for?
It's not high on my list of concerns either, i say "Scheiße" and even "****" all day long, when in private or amongst my friends. In written conversation - not so much, to be precise - never.
Written communication is prone to all sorts of misunderstandings. And I dont want to help these misunderstandings along further. So I stay calm, precise and polite. And I think it's a form of art to distinguish the two forms of communication. There are a lot of people that get triggered by even slight insults. Not to say they're right, but thats the way it is. This does not help communication along, to the contrary, so why not be polite? It costs nothing. And your point of view is not becoming stronger by being impolite. That's the last I will post about these psychological issues. But I have been holding back on this topic for too long. Following the TWTMC thread probably was too painful after all. Lots of brilliant guys in their own right here with very little communication skills. over and out.
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OMG, don't you realize an op amp buffer is NOT a regulator? The line regulation is exactly 0 (zero) dB. What comes in from the input gets out at the output, nothing less. In fact more, since the op amp adds his own crapola (noise, limited PSRR, CMRR, etc...) to the output
What for? Because I enjoy it and satisfies my crave for a challenge. Otherwise said, for exactly the same reason some people enjoy climbing the Everest mountain.
I'm very much tempted to call very loud "BS" on this statement. Every voltage regulator I know of has an internal reference it will compare it's output voltage to and regulate/adjust accordingly. How else would it regulate? An opamp buffer does just that. Assuming the reference is stable and low noise how could it be not regulating correctly? an opamp has LOTS of feedback, especially in gain = +1 config. Sometimes you appear to be SOOO scientific, then somtimes you seem to miss the most basic things. Or did I miss somethhing crucial here???
Have fun with your excercise. I wonder why you're in the diyAUDIO forum though...
EDIT: My last sentence sounded like I want to belittle your undertaking. That was not my intention. Just to make that clear.
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You can call it BS until blue in the face but, fact is, you are missing lots of crucial (aka basic) things here, I can only say you could use a trip back to the very basics. Do you understand the concept of “line regulation”?
I’m sorry, I can’t help more beyond this point, life is too short. Any decent basic electronics book will have the information you need to clear the muddy waters.
Your question about my contributions here is valid, and I’m asking myself the same more often than I would like to; the answer is there isn’t another forum with the same profile; while the ASR crowd is definitely, on average, more qualified than here (and some of the stuff they discuss is way over my head) that forum is not fun at all. It looks, on average, like a bickering place for cranky old farts.
There were times (10-15 years ago) when this forum was a place chock full of great engineers with a knack for audio, and multiple new ideas were developed. 95% of them left (I took myself an 8 years break), I’ll let you guess why, and were replaced by I’ll let you guess who/what.
I’m sorry, I can’t help more beyond this point, life is too short. Any decent basic electronics book will have the information you need to clear the muddy waters.
Your question about my contributions here is valid, and I’m asking myself the same more often than I would like to; the answer is there isn’t another forum with the same profile; while the ASR crowd is definitely, on average, more qualified than here (and some of the stuff they discuss is way over my head) that forum is not fun at all. It looks, on average, like a bickering place for cranky old farts.
There were times (10-15 years ago) when this forum was a place chock full of great engineers with a knack for audio, and multiple new ideas were developed. 95% of them left (I took myself an 8 years break), I’ll let you guess why, and were replaced by I’ll let you guess who/what.
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You can answer the question yourself by defining and calculating the “line regulation” for an op amp buffer.
You seem to believe the one and only voltage regulator important parameter is the “load regulation” which is variation of the output voltage to the load variation. Flash news, there’s much more than that. Why would we need for example a Jung voltage regulator, in general series regulators, parallel regulators, if we could simply buffer a reference with an AD797 and save the rest of the circuit?
You seem to believe the one and only voltage regulator important parameter is the “load regulation” which is variation of the output voltage to the load variation. Flash news, there’s much more than that. Why would we need for example a Jung voltage regulator, in general series regulators, parallel regulators, if we could simply buffer a reference with an AD797 and save the rest of the circuit?
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Guys, four separate AVCC supplies are not needed. ES9038PRO only uses two AVCC rails. Topping probably used four opamps to get enough current for 9038PRO. That's probably why they put 3-ohm resistors in series with the AVCC opamp outputs, so they could parallel two opamps (both in one package) to power one AVCC rail.
Moreover, the dac almost certainly sounds better using opamps. That's what most people find if they bother to do the experiment. Those people designing measurement dacs should probably stick to low noise voltage regulators instead.
Moreover, the dac almost certainly sounds better using opamps. That's what most people find if they bother to do the experiment. Those people designing measurement dacs should probably stick to low noise voltage regulators instead.
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How would they experiment without knowing what this experiment setup involves?
More unsubstantiated stuff from the master of FUD, that hasn't ever built anything beyond massacring otherwise perfectly fine boards.
Isn't the line regulation the same as PSRR?
And why the AD797 is not regularly used as voltage regulator - I always though this is due to the limited output current capability.
For all the rest, I don't know. You could shed some light on this, if you want to. If not, that's fine by me - I'll simply leave it at that and die in ignorance
No, not even close.
Hint: what you call "reference" for the op amp buffer needs to be, in fact, a very good low noise regulator, since whatever you are feeding in the op amp buffer (voltage variations due to "reference" element current and/or temperature, noise, etc...) will also come out of the op amp buffer. The only thing that the op amp may help with is the overall "load regulation" by potentially lowering the output impedance compared with the "reference". Which would be good, but only if it would be required; a competent engineer would attempt to figure this out, before designing in the op amp buffer. An incompetent engineer will say "an op amp buffer is good because it sounds better".
Otherwise, you will survive.
P.S. A whatever op amp (in inverting, non inverting, +1 buffer, -1 buffer, you name it, configuration ) input is not the power supply pin(s). Simple cause-effect relationship, by your logic any op amp gain stage is also a "voltage regulator".
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Can't see how this differs from any other regulator. It's reference needs to be low noise, or IOW - any noise on the reference will make it through to the output. Take the LM317 for example - there it's even worse because the reference voltage is amplified by a certain factor and with it all the noise on it.
Try harder. You could extend an op amp output current, for example like in the attachment, static source/sink configurations (if that really matters, which is again not proven) are as trivial to design, with two transistors. This still won't make an op amp a "voltage regulator".
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