[AllanS]

For various reasons I'm starting to poke at tube amplification beginning with the basic search question of why tubes?

The top search result landed on this Ken Rockwell page:
https://kenrockwell.com/audio/why-tubes-sound-better.htm

Being new to the topic, I found the entire article interesting and thought provoking.  Specific to my initial question, Ken's introductory generalizations speak to what may be fundamental considerations for someone deciding what topology best suits their preferences.

Understanding that everything depends on implementation, are these generalizations fundamentally accurate?

"Tube amplifiers sound better because of the euphonic distortions they add to the music...
Tube amplifiers measure poorly in the lab specifically because of these added distortions, but these distortions are often a part of what make them sound better.
Of course these are all very broad generalizations...but what are the distortions and other reasons tube amplifiers sound better?
Tube amplifiers have much more distortion than solid-state amplifiers, but most of it is second-order, which is quite musical.
Not only is tube amplifier distortion harmonious, it increases as things get louder - exactly as they do in a musical performance. As instruments play louder, or as you hit a percussion instrument or piano key more strongly, they generate more harmonic content. As notes decay, the percentage of harmonic content drops again. Tube amplifiers mimic this.
Just like our ears, musical instruments and just about everything else natural, tube amplifiers have the least distortion at the lowest levels. This is why a tube amplifier can sound great played softly, while with transistor amplifiers people are usually needing to turn it up to have it sound best.
Tube power amplifiers sound their best at the volumes at which you actually want to enjoy them.
Tube amplifiers overload gradually. Add more input and they distort more, but there is no precise level above or below which they suddenly start to clip."

[musicdre]

yes a lot of truth in that statement, imho.

[FullRangeMan]

Tube amps have a sound rich in Harmonics pleasant to the human brain, which makes them classic equip to listen music, for this reason they should not go out of fashion as long as the human being has this current brain configuration.

[Tyson]

The reason tubes sound so good is because they are inherently more linear than SS amps and thus need  far less feedback.  The grit and harshness you hear in an SS amp is a direct result of this feedback. 

Tubes are simpler and thus, better.

[FullRangeMan]

Some tubes are linear others not.

[AllanS]

There was mention that tube amps need and use less negative feed back, which leaves room for some. 
One thing that struck me is his comment that tube amps mimic natural harmonic distortion.  If tubes more accurately reproduce sound as you would experience live, why is eliminating distortion and the measurement of such elimination so hotly contested and controversial?  Is tube coloration a misnomer if it is in reality truer to “artistic intent”?
Maybe this is why I actually like the sound of my NAD T758.  It’s among ASR’s worst measuring amps.

[musicdre]

One thing that struck me is his comment that tube amps mimic natural harmonic distortion.  If tubes more accurately reproduce sound as you would experience live, why is eliminating distortion and the measurement of such elimination so hotly contested and controversial?  Is tube coloration a misnomer if it is in reality truer to “artistic intent”?
Maybe this is why I actually like the sound of my NAD T758.  It’s among ASR’s worst measuring amps.

really not trying to re-start the old subjective/objective debate here, but in the spirit of what AllanS just wrote, i read a think piece a while ago along the lines of great measuring amps being unable to sound great.  the idea being that the thing mfgs. do to reduce measured distortion actually result in more of the distortion being the unpleasant kind.    just an interesting idea, imho.

[AllanS]

really not trying to re-start the old subjective/objective debate here

Ditto.  Edit to add the topic of tube harmonics is something of a revelation to me - an epiphany of sorts.  I think it also add context to some of Nelson Pass’ tech articles I’ve read.

[FullRangeMan]

For the purpose of how the speaker see a tube amp the OPT must be taken into account, so I think the SQ will benefit from a big OPT, IMO.

[rollo]

Tube amps have a sound rich in Harmonics pleasant to the human brain, which makes them classic equip to listen music, for this reason they should not go out of fashion as long as the human being has this current brain configuration.

  Any Amp that uses phase splitting has the Humpty Dumpty effect. Meaning cannot put the signal back together properly after splitting it. The reason I prefer SET amps.

charles

[FullRangeMan]

  Any Amp that uses phase splitting has the Humpty Dumpty effect. Meaning cannot put the signal back together properly after splitting it. The reason I prefer SET amps.

charles

+1. SET amps are the way to go, a long other important features as Hard Wiring, copper or silver, tube rectification, Alu Chassis, etc the matter is complex.

[Tyson]

  Any Amp that uses phase splitting has the Humpty Dumpty effect. Meaning cannot put the signal back together properly after splitting it. The reason I prefer SET amps.

charles

Exactly.  I like SET amps the best, then Push Pull tube amps second best, class A Solid state amps next, and everything else is not a viable long term option for me.

Only thing, SET amps require a relatively high efficiency speaker with a decent impedance.  If you have that, then they are magical.

[rollo]

Exactly.  I like SET amps the best, then Push Pull tube amps second best, class A Solid state amps next, and everything else is not a viable long term option for me.

Only thing, SET amps require a relatively high efficiency speaker with a decent impedance.  If you have that, then they are magical.

  Agree. Especially two way deigns and subs. Owned planars, electrostatics, Bi-polar, line arrays, 3 ways and have settled with a two way design.

charles

charles

[Kw6]

+1. SET amps are the way to go, a long other important features as Hard Wiring, copper or silver, tube rectification, Alu Chassis, etc the matter is complex.

Fullrangeman,

Will it make a difference if the SET amp is in one chassis or in mono blocks?

[FullRangeMan]

Fullrangeman,

Will it make a difference if the SET amp is in one chassis or in mono blocks?

Difference in what area SQ ?
1) I dont like mono tube amps.

2) Also the ubiquitous stereo tube amps formula are a compromise, they use only one power Transformer for less cost.

3) The correct way to go with tube amps are both channels in the same chassis with two Power Transformers, one for tube Heating, other for the hi voltage supply.

[Kw6]

Difference in what area SQ ?
1) I dont like mono tube amps.

2) Also the ubiquitous stereo tube amps formula are a compromise, they use only one power Transformer for less cost.

3) The correct way to go with tube amps are both channels in the same chassis with two Power Transformers, one for tube Heating, other for the hi voltage supply.

Different as to better imaging, blacker background more find details. But your suggestion is good. I will seek out designs with dual mono power supplies like a mirror image for left and right channels in one box. What about the OPT?

[FullRangeMan]

Different as to better imaging, blacker background more find details. But your suggestion is good. I will seek out designs with dual mono power supplies like a mirror image for left and right channels in one box. What about the OPT?

The OPT are mandatory tô be two for Stereo.
Just being mono will no grant better sound, it will depend on the circuit and the construction.

[Kw6]

The OPT are mandatory tô be two for Stereo.
Just being mono will no grant better sound, it will depend on the circuit and the construction.

Ok thanks! One more question. Would you rather have an ANk interstage 300b mono with their own transformers or 300b monos that use capacitor coupling with similar circuit but OPT on the second set of monos use better iron like Hashimoto.

[FullRangeMan]

Ok thanks! One more question. Would you rather have an ANk interstage 300b mono with their own transformers or 300b monos that use capacitor coupling with similar circuit but OPT on the second set of monos use better iron like Hashimoto.

This is a complex question, my opinion is don't buy a 300B amp, this is a expensive tube, much less these ANKs they use PCBs.

Instead look EL34, KT66, KT88, KT150 amps as Dennis Head Inspire Fire Bottle, it accept all these tubes and use point to point wiring, you can order custom made amps from Dennis.

[AllanS]

  Any Amp that uses phase splitting has the Humpty Dumpty effect. Meaning cannot put the signal back together properly after splitting it. The reason I prefer SET amps.

charles

If possible would you please explain phase splitting in layman’s terms or point me to a reference so I can read up on it?  And how are SET amps different?

Do all these tube benefits apply equally in both pre amp and power amp applications?

Do hybrids compromise sound quality or do they offer benefits beyond efficiency that someone should consider?

Thank you.  This stuff is interesting but at times like this I wish I would have studied EE rather than ME.