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So then what do these mean? You seem to use many terms that really have no meaning in terms of competent amplifier performance.
Here's the deal: amplifiers exist to make sounds louder. Period. They aren't supposed to add "pop," "sizzle," "liveliness," "life," "soul" or any other such nonsense. And especially not "boom."
Anyone who thinks tubes are mostly about that 2nd and 3rd harmonic distortion can create such a result with Pkane's Distort software. I can save you the trouble and tell you that isn't where "tube sound" is coming from, but you can prove it to yourself if you wish.
The distortion from tube amps is not constant, it is level dependent. I don't think that pkane's software does that. Having said that, I have PKHarmonic, and not Distort.
BTW to @genesisaudiorack I don't think any of us have a problem with preference. The problem is claiming that something is what it isn't. I have tube amps, and every now and then I think of selling them and pocketing the difference. But every time I look at them, I can't bring myself to do it. I love them not because they are "more accurate". I am not even sure if they actually "sound better" even though there are reasons why they might. I love them because they are beautiful and put me in the mood for music.
I concur. Reckon it's not only amplifiers tho.
My mrs refuses to believe that my speakers are breeding, and insists it is simply me and my annoying "hoarding ways". Seems I now have three generations of Tannoy T12/V12s
(Perhaps I should suggest that it's actually the speakers inherent "whoring" ways...)
This is a topic that has been discussed over and over again.
My genuine feeling is that the separation of D-class amplifiers is definitely much better than that of tube amplifiers.
When playing music, it is very clear and bright, but this will lead to a very high frequency, because high separation requires prominent high frequencies to distinguish. However, tube amplifiers have very poor separation, but they emphasize low frequencies, so it sounds muddled together.
In terms of real listening experience, D-class amplifiers have too much high frequency, which can easily make people's ears tired. No one likes a woman screaming at home. Tube amplifiers do not have such a problem. Because they emphasize low frequencies, the high frequencies are not harsh and even have a hint of sweetness.
Pure tube amplifiers have very poor separation. Now I always use tubes as the pre-amplifier. After tuning, the D-class maintains a certain degree of separation without being harsh, and it's very pleasant to listen to!
I concur. Reckon it's not only amplifiers tho.
My mrs refuses to believe that my speakers are breeding, and insists it is simply me and my annoying "hoarding ways". Seems I now have three generations of Tannoy T12/V12s
(Perhaps I should suggest that it's actually the speakers inherent "whoring" ways...)
i am just about to get off the tube merry go round.
i have an HP8 tube amp but when i switch between it and my Midgard i am no longer sure i hear any difference whatsoever.
was convinced i did not long back.
my brain was easily led, i guess
You could buy a low powered tube amp you like. Load it with a model of your speakers impedance (power resistors, caps and coils), reduce voltage for unity or low gain, use it between source and SS power amp. You'll get all the sound you love with whatever power you need. You'll get all the sound of the tubes. Because there sound is a coloration and one any good SS amp can correctly reproduce. This is not conjecture either it is something I have done a few times.
Excellent post! This experiment would be even more convincing than a circuit simulation (which would also lead to the same conclusion, i.e. that the lf loudness effect is the primary contributor to the tube "sound").
@genesisaudiorack
I understand that you indeed hear something different in your tube amps but there is a scientific explanation to it: It is well proven, as you may have read more than a 1,000 times in this forum, that even small loudness differences are perceived as quality differences in our brain. Where this loudness increase comes from?
The answer is that as others have already pointed out in this thread, you like the bass amplification (let's put aside the psychologically-negative term "coloration") that is caused from the insufficiently low output impedance of the tube amp in combination with the inductive impedance of the speaker. These two components form a low pass RL filter, and any EE with a bachelor degree can easily explain you how it works. Pretty basic stuff.
There's no magic, no boom, no loveliness. Just preference that could also be satisfied with a parametric equalizer. Unless of course your tube amp's damping factor is also amplitude-dependent (in that case, a non linear element is introduced, and the term coloration becomes more relevant than before).
My two cents: Moving from tubes to class d solid state was easy. I learned a lot about listening from the tube amps because I truly love listening and they were well designed amps for their time that still sound good. Because I cared so much about the gear I was focusing more attention on the music. Plus I had a lot of additional interests wrapped up in them. Mostly learning about the history of hifi, its personalities and development, especially from the ‘40s through the early ‘70s. Those were some heady times and one could spend a lifetime listening through many of the products from those days with complete technical and musical satisfaction. All that aside, my new amp has more solid bass, cleaner mids and highs and, because I am hearing more of the sound of the original recording, I don’t notice any lack of warmth…only more of the details of the production and sound.
A a well known HiFi pundit once said to me, go buy a valve amplifier if you must, you might like what it does, but you'd better like what it does applied to everything you listen to!
"The cochlea is the part of the inner ear devoted to hearing. It is a 35 mm long spiral fluid filled tunnel of reducing aperture embedded in bone with 12,000 outer hair cells spread every 10 microns in sets of 4, each tuned to a different frequency.
Studies via instrumenting sets of outer hair cell neurons have verified the creation of harmonics within the cochlea. (bolded by me) Those studies documented already in 1924 that the human ear produces such harmonics by itself. Inspecting this data, the second harmonic of a 1kHz fundamental tone is 50dB above the threshold of hearing. The ear creates significant levels of the second harmonic. To an amount of nearly 10% of the fundamental for sound pressure levels (SPL’s) of 90dBA and above. Even for the moderate SPL of 80dBA, the 2nd harmonic is at the equivalent of 65dBA or normal voice level, and the 3rd at 45dB. This is still ~40dB above the average human threshold of hearing, yet one does not hear the harmonics as a separate tone. Only a single pure tone is heard.
The ear/brain appears to be able to completely suppress the sound of a range of harmonics if they conform to this specific pattern. This pattern is the aural harmonic envelope. It follows that this same mechanism will mask harmonics arising in the sound reproduction chain if they follow this pattern.
If the harmonics do not follow this pattern, the ear brain indeed detects these as new tones. Therefore, we perceive any sound system that generate this harmonically consonant envelope as transparent, for all but extreme frequencies and sound pressure levels. Those sound systems that generate harmonic overtones outside the aural harmonic envelope will be perceived as distorted, less transparent.
This paper seems to say that the reaction of the cochlea varies with amplitude. That would explain the observation of both @Keith_W and @Blumlein 88 :
Anyone who thinks tubes are mostly about that 2nd and 3rd harmonic distortion can create such a result with Pkane's Distort software. I can save you the trouble and tell you that isn't where "tube sound" is coming from, but you can prove it to yourself if you wish.
I have replaced my headphone amp (FiiO K7 THX) with a Schiit Vali3. After rolling a few tubes, I settled on a GE5670 dual triode for the pre-amp. The Vali3 has a Class AB output section.
Just running without equalization, I perceive a tighter (faster?) bass response. My testing includes tracks with close-miked acoustic bass. I like music with a lot of acoustic instruments. I enjoy it when the musicians get into the same flow (groove?). Sound stage and isolation are important to me. The Vali3 beats the K7 here. The mid range (vocals) are more forward on the K7, but seem more life-like on the Vali3
Then, to satisfy my 75 year old ears I add some treble boost with the Loki+ analogue tone controls. I am spending hours enjoying a relaxing, engaging, and satisfying musical experience. The old adage " I am hearing details I never heard before" applies
"The cochlea is the part of the inner ear devoted to hearing. It is a 35 mm long spiral fluid filled tunnel of reducing aperture embedded in bone with 12,000 outer hair cells spread every 10 microns in sets of 4, each tuned to a different frequency.
Studies via instrumenting sets of outer hair cell neurons have verified the creation of harmonics within the cochlea. (bolded by me) Those studies documented already in 1924 that the human ear produces such harmonics by itself. Inspecting this data, the second harmonic of a 1kHz fundamental tone is 50dB above the threshold of hearing. The ear creates significant levels of the second harmonic. To an amount of nearly 10% of the fundamental for sound pressure levels (SPL’s) of 90dBA and above. Even for the moderate SPL of 80dBA, the 2nd harmonic is at the equivalent of 65dBA or normal voice level, and the 3rd at 45dB. This is still ~40dB above the average human threshold of hearing, yet one does not hear the harmonics as a separate tone. Only a single pure tone is heard.
The ear/brain appears to be able to completely suppress the sound of a range of harmonics if they conform to this specific pattern. This pattern is the aural harmonic envelope. It follows that this same mechanism will mask harmonics arising in the sound reproduction chain if they follow this pattern.
If the harmonics do not follow this pattern, the ear brain indeed detects these as new tones. Therefore, we perceive any sound system that generate this harmonically consonant envelope as transparent, for all but extreme frequencies and sound pressure levels. Those sound systems that generate harmonic overtones outside the aural harmonic envelope will be perceived as distorted, less transparent.
This paper seems to say that the reaction of the cochlea varies with amplitude. That would explain the observation of both @Keith_W and @Blumlein 88 :
Part of tube sound is likely due to a voltage divider effect between the amp's output impedance and the speaker's input impedance. The amp's output impedance will be fairly stable over frequency, while the speaker's will vary quite a bit with frequency. The speaker in effect modulates the tube amp's response by the varying impedance over frequency the speaker presents to the amp. So that tube amp is likely to produce a different type of tube sound when different speakers of different impedance characteristics are connected to it. A low Zout S.S. amp will not be affected by this mechanism, what with e dozen or so milli-ohms of output Z they usually have. The S.S. amp looks at the speaker and say, "Speaker, you are coming along with me, do you understand? You do not get to argue, sorry.".
I have been reading about this for years, please, can somebody help me, and pinpoint a study showing this is actually a scientific fact? Has there been any respectable double-blind study showing that some people can differentiate a tube amp from a solid amp and actually prefer the tube sound? You know, without this, this whole conversation has no ground.
"The cochlea is the part of the inner ear devoted to hearing. It is a 35 mm long spiral fluid filled tunnel of reducing aperture embedded in bone with 12,000 outer hair cells spread every 10 microns in sets of 4, each tuned to a different frequency.
Studies via instrumenting sets of outer hair cell neurons have verified the creation of harmonics within the cochlea. (bolded by me) Those studies documented already in 1924 that the human ear produces such harmonics by itself. Inspecting this data, the second harmonic of a 1kHz fundamental tone is 50dB above the threshold of hearing. The ear creates significant levels of the second harmonic. To an amount of nearly 10% of the fundamental for sound pressure levels (SPL’s) of 90dBA and above. Even for the moderate SPL of 80dBA, the 2nd harmonic is at the equivalent of 65dBA or normal voice level, and the 3rd at 45dB. This is still ~40dB above the average human threshold of hearing, yet one does not hear the harmonics as a separate tone. Only a single pure tone is heard.
The ear/brain appears to be able to completely suppress the sound of a range of harmonics if they conform to this specific pattern. This pattern is the aural harmonic envelope. It follows that this same mechanism will mask harmonics arising in the sound reproduction chain if they follow this pattern.
Do we know if this "aural harmonic envelope" (AHE) is the same for different people? I wouldnt think so. If a musical instrument has the same AHE as me, do I just hear the fundamental, or a lot less overtones? And this would be constantly changing as the harmonic envelope of the instrument changes, think about a forte piano note. If the AHE of the note changes with the decay from similar to yours to different you would not hear overtones at the begining of the note. Ive never heard this effect. Likewise can be said for an amp that changes its AHE with level, as some do. Whats missing from the above explanation?
