The topic of objective/subjective implicitly IS the discussion. The thread starter had asked for an (objective) explanation for why some amplifiers sound (subjectively) grainy, while others do not. Yes?
What it has not been is any kind of conflict laden discussion. The search for truth does make some people uncomfortable, however, I would like to think that most of us here are adult enough to handle that without unwarranted proctoring or suggestions of censorship.
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Not familiar with your other references but my F5 clone had a shocking amount of grain. The F7 improved noticeably but still was not grain free. On this basis i had practically given up on building an XA25 but your comments seem very encouraging.
What is more interesting is none of the reviews of these amps mention anything related to grain. One possible view is that what some listeners call grain others interpret as a more dynamic and forward sound.
Your question is part of a much larger one. Which is, why do electronic components, that all feature objective measured performance supposedly well below the threshold of human detection, still seem to sound different from each other? We use terms such as grain, liquidity, sweetness, warmth, etc., to subjectively describe the differences some of us believe we hear. Yet, there seemingly remains a disconnect between the objective measurement and the subjective experience. The objectivist explanation for that seeming disconnect is that, we do not actually hear any difference, it's all psychological. Meaning, it's all self-delusion. There is undoubtedly truth to that notion in cases, but not all cases.
I often wonder how many true objectivists have purchased pre and power amplifiers that are more costly than an equivalent mass-market A/V receiver or integrated amplifier from Far East manufacture. To have purchased anything more pretentious does not seem logical for a true objectivist, because mass-market amplification routinely features objectively unimpeachable measured performance, as far as human perception is supposedly concerned. So do digital sources, for that matter. Objectively, we have indeed had 'perfect sound forever' since 1983. Subjectively....? Hmm
Interesting segue to the world of Ayn Rand
Your question is part of a much larger one. Which is, why do electronic components, that all feature objective measured performance supposedly well below the threshold of human detection, still seem to sound different from each other? We use terms such as grain, liquidity, sweetness, warmth, etc., to subjectively describe the differences some of us believe we hear. Yet, there seemingly remains a disconnect between the objective measurement and the subjective experience. The objectivist explanation for that seeming disconnect is that, we do not actually hear any difference, it's all psychological. Meaning, it's all self-delusion. There is undoubtedly truth to that notion in cases, but not all cases.
I often wonder how many true objectivists have purchased pre and power amplifiers that are more costly than an equivalent mass-market A/V receiver or integrated amplifier from Far East manufacture. To have purchased anything more pretentious does not seem logical for a true objectivist, because mass-market amplification routinely features objectively unimpeachable measured performance, as far as human perception is supposedly concerned. So do digital sources, for that matter. Objectively, we have indeed had 'perfect sound forever' since 1983. Subjectively....? Hmm
Interesting segue to the world of Ayn Rand
Interesting segue to the world of Ayn Rand
What does Rand, and her right wing political philosophy, have to do with anything written by anyone in this thread?? Do you even know yourself to what you're attempting an allusion, because I do not fathom it. So, please, do enlighten us all.
I said this 'tongue and cheek'. When ever I hear the term Objectivism, I think of Ayn Rand and having to grind though The Fountainhead in college. If I offended anyone, I appologize.
Exactly, and one should also remember, that a program from CD can come already with some grain. And if one amp exaggerate this grain or add to it, someone believeves that this amp is more detailed and accurate. Hence, trying to understand real quality of amp, one must have top quality program and source, that gives no any grain. If an amp will produce some grain even with such source, than one could judge.
Problem is, top quality programs tend to give top quality sound (better than reality), so harder to perceive differences. And without proper preamp (for proper impedance matching) proper conclusion is also difficult (and can be misleading). I don't want a system that sound good only with top level programs and DACs. There is no one amp that excel at everything. At the end of the day, I choose the one that makes me happy the most. One needs to have a formula for this
After quite a long my personal evolution in audio, I have come to SE GM70 integrated tube amp (tubes with "iron" plates, graphite ones add some minor grain). It allows me to hear program as it is. If program with grain, I hear it, if program perfect and has no grain, I also get perfect grainless sound. Next to this amp in my preferences goes NoNFB class A SE transistor amp, next to it - class A with some NFB
maybe you are just hearing more of the recording that can be where the grain is.
It is like a picture of an old face ... with a sharp lens you will see every wrinkle.
I personally like extreme trasparency ... with some tweaking like using solid core/litz interconnects ?
like them expecially with digital sources
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Following your way of thinking, I would say, that lens could be durty (covered by oil film), could be clear and perfect, and could be scratched. If scratched, in addition to picture's wrinkles, such a lens will create additional visible wrinkles, and one never knows, whether one has the same amount as on the picture, or more than that. If one always see many wrinkles at any picture of even young girl, than the lens is scratched.
Durty lens is even worse, since wrinkles are some analogy of program's low level detailes, that will be lost.
Durty lens is even worse, since wrinkles are some analogy of program's low level detailes, that will be lost.
Transparency is a subjective quality measure. In my book, transparency should be 'resolution with accuracy'. Resolution is when you can hear details. This detail is not critically important as in most music especially live ones we don't hear rats running on the back stage. Worse is when the resolution is not accompanied by accuracy as resolution is often accompanied by intermodulation that makes sound inaccurate. Dynamic compression, is less serious issue, also part of inaccuracy. Class A can easily have this kind of inaccuracy.
Actually, no it isn't. Transparency is achieved when nobody can tell the amplifier apart from an ideal "wire with gain", assuming said gain is identical. The (worst-case) limits for this are roughly -
Frequency response: within 0.3 dB, 40 Hz - 16 kHz (including damping factor - seaker interaction)
THD and IMD: -80 to -100 dB (depending on who you ask) or better at worst-case listening levels (103-110 dB SPL tops), with no major surprises in the low ultrasonic region
Noise: about 0 dB SPL at listening position or lower with given transducers
Note that this may be conditional depending on transducers used. Wideband speakers won't be as critical with damping factor as multi-way ones, low sensitivity speakers will mask noise, high sensitivity speakers will be gentle on amplifiers that struggle at high power but do fine at lower levels, and load impedance will affect both distortion and damping factor effects.
People are often easily mislead by the false detail of some low-level odd-order distortion. In a system that has other problems, such as perhaps too much low-level even-order distortion, just a little added odd order distortion can make it seem more clear and detailed. Its a common problem for people working on dacs and amplifiers who have not learned how to discern when seeming detail is actually false. Easier said than done until one has had enough experience listening to false detail vs ultra-low distortion detail. For me at least, listening for symptoms of IMD on known clean recordings is very useful.
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Speaker distortion tends to be lower for smaller cone displacements. I find I can hear problems with electronics better at rather low volume levels and in the speaker near field. Other people seem to prefer listening at higher volume levels. Whatever works for someone is okay, but maybe good to carefully try both ways to see which is more useful for each designer.
For HD/IMD, it matters quite a bit what the order is. 2nd and 3rd harmonics are less objectionable sounding, and less noticeable by most people than higher order harmonics. That is why using single numbers for HD or IMD is not sufficient, IMHO. In addition, it matters what distortion is as a function of frequency and of level.
To make things even more complicated, how humans hear is not completely correlated with how we measure. Therefore, one should evaluate equipment both ways: measurements and listening tests.
All the foregoing IMHO, of course.
Vlad has a good point: how does one know whether we are hearing grain or detail (same program material). Since nobody has a wire-with-gain, we are stuck comparing one amp to another to make subjective assessments (it's fairly clear from the earlier parts of the thread that we don't know how to measure the grain—not that it couldn't be measured, but nobody knows what measurement to attribute to the phenomenon). When I assess grain, I do it on relatively smooth sustained sounds, notionally vocals, for which I feel we humans have good heuristics as to what "natural" should be. I don't know a better way.
Vlad also points out that different topologies have different perceptions of grain. His favorite is Tubes, followed by no-feedback class A, followed by minor feedback. That progression is a widely held view. What hints does that provide us? Is there something about thermionic emission that is inherently more stable/less-grainy than transistors? Or is it just that even-order distortion is somehow covering the grain?
How about hints from feedback topologies? What in the feedback loop adds grain? Some resistors have current-dependent noise, do these become a candidate for grain (see my earlier post about resonance) in feedback loops?
I ask these questions out of naiveté in the hope of provoking some thought among our physics-oriented members.
Vlad also points out that different topologies have different perceptions of grain. His favorite is Tubes, followed by no-feedback class A, followed by minor feedback. That progression is a widely held view. What hints does that provide us? Is there something about thermionic emission that is inherently more stable/less-grainy than transistors? Or is it just that even-order distortion is somehow covering the grain?
How about hints from feedback topologies? What in the feedback loop adds grain? Some resistors have current-dependent noise, do these become a candidate for grain (see my earlier post about resonance) in feedback loops?
I ask these questions out of naiveté in the hope of provoking some thought among our physics-oriented members.
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Sure, it is not even-order distortion. IMHO, one good property of tubes - interelectrode capacities do not depend on voltages applied. Other good - signal voltage swings at tube stages are one or two orders of magnitude higher, than at transistor stages, and all possible sources of low-level grain (like for instance imperfect welded joints, and other imperfections from parts, like from capacitors etc.) are than reduced by 30-50 times by output transformer. This does not happen at transistor stages. And, linearity of tubes stages without NFB is usually better, than NoNFB transistor stages.
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