I see what you mean, Jan.
My belief is that both effects are important.
1) Each person has a distortion characteristic preference. So if you have two different amp designs, both distorting a similar amount but in different ways, then some people will prefer one and some will prefer the other.
2) Each amplifiers distortion will certainly be music dependent. So any one person may prefer a certain type of music on one amp and a different type of music on the other.
If this is true it explains why it is so very difficult to consistenty correlate people's preferences with circuit measurements.
I am a believer that if an amplifier had no distortion at all then almost all people would prefer it on almost all music. This is certainly my personal experience.
My belief is that both effects are important.
1) Each person has a distortion characteristic preference. So if you have two different amp designs, both distorting a similar amount but in different ways, then some people will prefer one and some will prefer the other.
2) Each amplifiers distortion will certainly be music dependent. So any one person may prefer a certain type of music on one amp and a different type of music on the other.
If this is true it explains why it is so very difficult to consistenty correlate people's preferences with circuit measurements.
I am a believer that if an amplifier had no distortion at all then almost all people would prefer it on almost all music. This is certainly my personal experience.
traderbam said:
Yes, makes sense. But on 1) I would think that because people are built according to the same basic blue print, they would find the same type of distortion objectionable, which would have to do with the 'unnaturalness' of the harmonic contents. Generally people find the same type of sounds dissonant.
Although they may prefer certain types of music which can be different; this is probably largely culturally determined.
Are we going too far off-topic here?
Jan Didden
It is always hard to second guess what meaning Mike intends by his terse retorts. Perhaps he thinks DIYAudio charges by the word. 
I am quite happy with the "airy" descriptor that Pavel used. Other examples: "fast", "compressed", "throbby", "narrow", "deep", "grainy", "aggressive", "smeared", "bright", "dark", "distant", "in your face"....these all seem perfectly valid ways to describe different distortion presentations to me. Why not?
I am quite happy with the "airy" descriptor that Pavel used. Other examples: "fast", "compressed", "throbby", "narrow", "deep", "grainy", "aggressive", "smeared", "bright", "dark", "distant", "in your face"....these all seem perfectly valid ways to describe different distortion presentations to me. Why not?
Hi, Traderbam,
Do you know the "translation" of those "6moons" words into "diyaudio" words? Each effect must have a/some technical explenation/which distortion is involved.
For example, I found out 1 term, "fast" amp and "slow" amp. At first, I don't understand this. If a song is 5minutes, played with any amplifier it will be still 5minutes length. With "fast" amp it is 5minutes length. With "slow" amp it is still 5 minutes length of play.
Then I found out it is TIM. An amp with slight TIM is said "fast", another amp which is free of TIM is said "slow" amp. With amp that has slight TIM, the trebles are more "sparkling", this is what they called "fast" amp. Interesting, isn't it 😀
PMA said:
It may be easily translated on the technical language: crossover distortions may be very small and not audible on human voices, but they kill naturality of reverberation. Reflected sounds have different coloration because of frequency-dependent damping of surfaces that reflect it. Crossover distortions screw down the picture.
Reverberation is what creates imagination of air and space.
lumanauw said:
Lumanauw,
Try as I do to cover all details there is always a part of the picture left out. There was a load connected as I was trying to simulate the effects of a normal situation and the speaker load is a big part of that. My speakers are Martin Logan SL-3's.
I do think your thoughts that the fundamental wave being there is correct, now that I think about it. You never know what it might excite. I'll have to try this.
Without thinking it through, my first thoughts would include the same setup as before, the inclusion of a 1khz (to start) signal at a normal to high level while monitoring the spectrum. The scope software can be setup to report the level of the harmonics out to the fifth. and the interference is plainly visable in the spectrum as I pass the supplies over the input stage. It should be interesting.
Can You think of anything I'm missing here?
Regards, Mike.
That's right.
I once listened to two LP sources side by side at a hifi show on the same system. One was a Linn LP12 and the other was some cheaper brand which I don't recall. It was astonishing that the same track played on the LP12 actually seemed to last longer. It didn't of course, but that's how it sounded. It also sounded much more lifelike and musical.
I maintain that this is because the brains perception of time depends on the rate at which information is received. A really good system will convey significantly more "interpretable" information during a track than a poor one.
I have witnessed this myself as I have made step changes in circuit performance. Not only does a track seem to last longer but I remember more detail about it afterwards. Like the way a certain cymbal beat built up or subtle pitch changes or even, say, the emotional expression of an elongated pause in the lyric of a Kate Bush song.
mikeks said:
Air and space is a real effect, It's the reason for attempting to simulate out any source of distortion and noise below an unachievable level.
I heard the effect just last week after building an LM3886 chip amp to play with grounding scenarios. With the chip amp the sense of being able to hear into a live recording was lost and the sense of space was clearly collapsed.
I don't want to get into subjective/objective, measurement discussion, just to point out that all of the parts of the music that make it sound real are buried in the fine detail and the problems with our circuits tend to obliterate them as well as masking them through the various distortions that are generated. You can hear the air walking into a large auditorium.
Years ago I remember comparing a view from the pitchers mound at a ball game on two tv monitors; the one was two D and flat with no resolution behind the fence, the other you could read a cup label 6 rows back. Audio resolution is the same.
Regards, Mike.
Hi, Mike,
Don't forget ear plug 😀 1Khz to the speaker is very annoying.
I still think the best way to view this is through a distortion meter. I don't know if you could view this via FFT, because the comparison of the fundamental and the spikes in the leftovers are very big level difference. Maybe you could eliminate the fundamental first, then put it into FFT of yours? By passive T-notch filter, maybe?
Don't forget ear plug 😀 1Khz to the speaker is very annoying.
I still think the best way to view this is through a distortion meter. I don't know if you could view this via FFT, because the comparison of the fundamental and the spikes in the leftovers are very big level difference. Maybe you could eliminate the fundamental first, then put it into FFT of yours? By passive T-notch filter, maybe?
Hi, Traderbam,
Got another 2 😀
More punch = amplifier that has quite big 2nd harmonic, the bass is preferable (auditioned as better, more solid bass)
Airy/lifelike = seems to be the effect that the auditioners (who don't understand electronics) get when they hear an amp which is marginally stable.
I read somewhere that there is a designer who intentionally made the square wave test not perfect square, but oscilating at the ends. He knows this (he also know how to make perfect square), and he intentionally makes the square ripples at the ends. This is all because of sonics requirement (as long as the amp doesn't turn into oscilator, offcourse 😀)
One thing I know. Making amp sometimes cannot fullfill "as I liked it", but rather to fullfill what the customer wants. Why? Because the customer is the one who is holding the money, not the amp maker 😀
This is more difficult than making an amp that is technically correct. Have to know first what the customer wants, then studying what is that he is hearing, translate it into technical specification (more likely, what distortion he wants 😀), then intentionally made that technical "wrong-ness" in a certain degree that doesn't harm the amp (doesn't turn into oscilator or unstable).
Adjusting how much this "wrong-ness" is also very difficult. Too little or too much is going to be rejected by the customer too 😀
Got another 2 😀
More punch = amplifier that has quite big 2nd harmonic, the bass is preferable (auditioned as better, more solid bass)
Airy/lifelike = seems to be the effect that the auditioners (who don't understand electronics) get when they hear an amp which is marginally stable.
I read somewhere that there is a designer who intentionally made the square wave test not perfect square, but oscilating at the ends. He knows this (he also know how to make perfect square), and he intentionally makes the square ripples at the ends. This is all because of sonics requirement (as long as the amp doesn't turn into oscilator, offcourse 😀)
One thing I know. Making amp sometimes cannot fullfill "as I liked it", but rather to fullfill what the customer wants. Why? Because the customer is the one who is holding the money, not the amp maker 😀
This is more difficult than making an amp that is technically correct. Have to know first what the customer wants, then studying what is that he is hearing, translate it into technical specification (more likely, what distortion he wants 😀), then intentionally made that technical "wrong-ness" in a certain degree that doesn't harm the amp (doesn't turn into oscilator or unstable).
Adjusting how much this "wrong-ness" is also very difficult. Too little or too much is going to be rejected by the customer too 😀
Wavebourn said:
Nonsense. I made a comparison of 2 true class A amplifiers, both with very low distortions and with almost unmeasurable distortion at low level. My experience is different - distortion brings excessive "air" and "space".
lumanauw said:
Your right, I'll try a load resistor instead. The nice thing about the FFT is the fundamental is on one side of the screen and any harmonics are still plainly visible. I set it up for peak hold, wait for it to stabilize, then introduce the interference. Any change is easily seen.
Regards, Mike.
Anyone care to have a go at my question from page 28?
PS: I was once looking at a Cambridge University undergraduate entrance exam paper. I wasn't taking the exam. I remember it because the questions were so unusual. The one I recall was:
"How high can a grasshopper jump?"
I think the examinee was expected to answer this question within 30 minutes or maybe 45. I doubt the answer "Sorry, I cannot provide an answer because there is insufficient information" would have satisfied the examiner.
traderbam said:
Traderbam,
It's early in the morning here, so forgive me if I don't have it all together, but there are two parts to your question that may be ambiguous in interpretation.
First, you said that you want "it" to have 30 dB of gain at 50 kHz. Did you mean 30 dB of open-loop gain at 50 kHz, or 30 dB of closed loop gain at 50 kHz (or, possibly, 30 dB of feedback at 50 kHz)?
Secondly, you said you wanted -90 dB of Closed loop distortion. At what frequency do you want that? Can I assume that you want -90 dB distortion in closed loop at frequencies below the open-loop corner (where distortion generally begins to increase)?
OR, do you want -90 dB of distortion at 50 kHz?
Again, I may be missing the obvious here, as it is early in the morning. I'm terrible at trick questions like the grasshopper question.
How many grooves does a typical LP have?
Cheers,
Bob
Good morning Bob. Get that pot of coffee on! 😴
No tricks. No "right" answer is sought. Make up your own assumptions. Put a stake in the ground and show the thought process.
+30dB closed loop gain...with corner at 50kHz.
distortion -90dB or better at all audible frequencies.
My question is in response to a query about how fast transistors really need to be to make a 20kHz bandwidth amp.
No tricks. No "right" answer is sought. Make up your own assumptions. Put a stake in the ground and show the thought process.
+30dB closed loop gain...with corner at 50kHz.
distortion -90dB or better at all audible frequencies.
My question is in response to a query about how fast transistors really need to be to make a 20kHz bandwidth amp.
