So, in essence, you're claiming not measurable or infinitesimal electronic differences. Or have you not actually measured your tuned-by-ear setup compared to your original design to see if there is a difference?
It is certainly not unimaginable that the kinds of changes in implementation manifesting in different layouts and parasitics. At which point we're talking real changes in the end-to-end transfer function. Then we'd have to get back to magnitude of change and whether those changes are remotely plausible.
Anyhow, good luck. I certainly admire your willingness to take the leap.
What possible candidates aren't reduced by the massive amounts of feedback in modern op-amps (talking line-level stuff here)?
I highly doubt this given that the standard set of measurements serves far more demanding applications. If true, why does it seem that no one in audio has found it? If someone found the "key" measurement to this quality then they should be able to dominate the high end audio market.
I used to think a bit along the same lines, but realized there's no consensus and thus no pattern to subjective ratings of audio electronics. For every guy that says op-amps and ceramic decoupling caps sound terrible, you have $10000+ products with both winning awards. NOS DACs were in fashion for a while, then PCM1704 and AD1862 were the best thing since sliced bread, and now the evil sigma-delta is somehow acceptable and being peddled by the likes of Ayre. I mean, there are highly lauded Class D designs now...
Simply put, given the factual evidence and our knowledge of cognitive bias, I do not see how one comes to the conclusion that there exist audible and measurable flaws, able to be correlated with "sound quality" which have remained undiscovered since the dawn of T&M equipment.
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This is what most everyone says they want. As you indicate below, what many really want is something that "sounds good."
This indeed blurs the line between creation and reproduction.
Someone may hear a tube amp and it sounds better to them than a solid state amp. They may not have a lot of training or knowledge about audio (or they might but still), so they assume that sounding better means it's more accurate, that it must be more like the original performance.
There's a quote regarding music production that "some" might apply as well to reproduction: "If it SOUNDS better, it IS better." Duke Ellington.
Well, yes, there's that part for sure. But IIRC Robert's using some pretty big components and there's a real chance for some sort of incidental coupling.
I'm not holding my breath though.
Feedback in modern opamps is dependent on frequency. Its 'massive' at LF but considerably less so at HF.
Would you say that ADSL was a 'far more demanding application' ?
That's really easy to answer - because no-one's looking for it. Like Scott they think its not actually there. Why would anyone look for something they believe doesn't exist?
Marketing isn't that simple. But I do agree that once the measurement is developed it would act towards a commoditization of high quality audio, something I'm all in favour of.
No consensus about what's best/preferred I would agree but that doesn't entail no pattern in terms of subjective descriptions.
In order to discern patterns its important to exclude purely subjective opinion. 'Sounds terrible' is one such purely subjective opinion which should be discarded.
Looks to me as if you've got your chronology seriously confused here 😀 For a start Ayre has been using S-D DACs from its very first DAC design. But they're inconsistent in that they'll say 'feedback is bad' yet turn a blind eye to feedback inside the DAC chips they're using (S-D techniques depend on feedback).
Indeed so yet there have been technical advances reflected in their traditional measurements.
I think the tone control should not be baked-in to the device. Problem is, tone controls and EQ have a bad reputation due to poor implementations early on. You now have a group of customers who basically want tone control but only if they can't touch the knobs.
ADSL would be more demanding considering the frequencies involved, sure.
DAC chronology aside, one can find dozens of proponents of every possible way to build a DAC, pre-amp, or power amp. Even if we discard the "sounds terrible" reviews.
You're certainly entitled to your opinions, but I'll invoke Occam's razor here and suggest that if you make a pretty box with a high price tag and have good marketing copy then you'll move product in this industry and people will write / speak glowingly of their newest shiny object.
Indeed so. Its important to look beyond the preferences in order to attempt an understanding of what's happening in the electronics.
I don't disagree (I have no intention of marketing pretty, expensive boxes incidentally) but I can't see what your assertion has to do with Occam's razor.
All I usually do is is check frequency response and noise floor. Then listen, listen, listen. Once I find a nice part for a circuit application I just log it in my head.
The most critical parts of the circuit is anything that deals with the speech frequencies on up. Power supply impedance at high frequencies is crazy important too. This all requires, of course, your op-amp is not sloughing off things because of marginal speed.
This is not a leap for me. I think about these things naturally and have since the early 80's. And the curmudgeonly comments like the ones made recently right on this thread are just part of doing business for me; I've heard it all, largely before most of us were ever online as a matter of fact, and really don't care about detractors except I do run out of time and energy to post sometimes.
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I think the conclusion that's easiest to arrive at here is that there is nothing to find, that's all.
I'm not interested in what's the 'easiest' conclusion, rather the most audibly satisfying one.
Three suggestions:
In the case of an inverting topology, not to have in every schematic such extreme potential difference so instead of the common place direct grounding of positive inputs, add resistance. Better though that potential difference that is required is calculated as needed.
.In the case of output loads observing manufacturers recommendations, particularly for
capacitance loading, - ignore at your peril. There should be much humor followed by
discussion on the forum with any op amp circuit that attempts driving beyond
recommended guidelines.
Far more use of external devices ie fets and bipolars, to do actual load driving.
The questions is how do small, but measurable differences translate into sound character. We don't have any definitive answer.
Let me remind you of "metal detectors". The contemporary ones have large displays showing you all the numbers involved in the measurement. Yet it's still easier to use the thing based on the audio signal. There are objects that you would miss if you were to look at the numbers only with no audio.
Another bad analogy...
Basic metal detection the beep just alerts you something is there, very basic, whereas with a numerical display you can get a lot more information, such as depth etc.
How your analogy equates to designing some electronic equipment I don't know, perceptions can be fooled and are influenced by other senses.
There are things in music reproduction that cant be equated to anything as such because they are formed in our head, such as soundstage....
Basic metal detection the beep just alerts you something is there, very basic, whereas with a numerical display you can get a lot more information, such as depth etc.
How your analogy equates to designing some electronic equipment I don't know, perceptions can be fooled and are influenced by other senses.
There are things in music reproduction that cant be equated to anything as such because they are formed in our head, such as soundstage....
Hi Robert,
Just went to have a look at the site of Lounge Audio, and it all looks quite nice ... without the silly prices some high end producers ask.
Just a question, in the text describing the MC step up amp, it is mentioned that it has an optically isolated power supply. This made me very curious to find out a bit more about how this works and what the advantages are.
Tnx for your reply, vac
Just went to have a look at the site of Lounge Audio, and it all looks quite nice ... without the silly prices some high end producers ask.
Just a question, in the text describing the MC step up amp, it is mentioned that it has an optically isolated power supply. This made me very curious to find out a bit more about how this works and what the advantages are.
Tnx for your reply, vac
Scott, that's about as clear as a glass of mud!
Of course one could measure "differences" between SET and say a HALCRO (just to pick two items on opposite ends of the THD scale), but what would that tell you? Ok, there is a difference.
Now what?
What could you do with this "data"?
What could you predict?
Take a few amps/devices from the "middle of the pack" somewhere near the mean or average of these two from opposite ends of the spectrum, this information will tell you nothing much about their subjective presentations - UNLESS you think that anything that measures nearly the same sounds nearly the same in all regards? Similar perhaps, but not the same.
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Many here seem to think that this is not the case - and that DBT/ABX shows otherwise. If so, your quest for "fidelity" is over, you don't need to do anything more. In your world it's as good as it can be or ever get,except for something like better woofers or more bass extension in your speakers, or perhaps lower THD/IM speakers. But for electronics? It's a solved problem.
Forget about those who buy stupid expensive stuff and put gold plated monkey coffins, and gleaming jewel encrusted towers of lost civilizations into their listening room (heck of a visualization there, eh?) - We're DIY! We can build whatever we need with a handful of chips and some through hole parts, when needed. What other people do is no criteria for this matter.
We can shut this thread down now - it's been decided. Right?
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