Damping Factor - Interesting article

atmasphere,
I deleted my old post questioning your article as I misinterpreted what your point was and where you were coming from. Put my head into a different mindset and completely agree in principle w.r.t. what you were communicating w.r.t. constant power for a tube output configuration. I don't have a blind attachment to 0 output impedance / infinite damping factor, and I expect most who do don't even know the details of why and why it may not be best from a system standpoint.

Most modern speakers are simply wrong because they have uneven impedance curves and their impedance is too low in the bass region which then means you need amplifiers with low output impedance/high damping factors/negative feedback/high current supply to try to correct these electrical flaws.Two wrongs trying to make a right.When what we should be using is speakers with benign impedance curves in combination with current drive /high output impedance amplifiers because current drive amplifiers sound so much better than voltage drive.http://education.lenardaudio.com/en/12_amps_8.htmland  https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&u...

It is not an electrical flaw in the speakers. It is primarily a mechanical design choice. The site you linked is good, but it is easy to draw the wrong conclusions if you don’t read in depth.

A pure current feedback output is not ideal as it will provide a peaky frequency response, and provides no additional electrical damping for the drivers which can be beneficial.

The damping factor the speakers see is never near 0 either due to the crossover impedances.

Neither was is really "wrong", just different and the right answer is probably somewhere in the middle ... though I would say most accurately, the correct answer is speaker specific amplification with an amp per speaker, but that is a tough nut for most companies to crack and not easy to market. Good on SGR tackling it at some level.

How does damping factor apply to a zero feedback amp like an ayre .

@david_ten wrote:

"1. Regarding:

My understanding is that low damping factor generally calls for high amounts of global negative feedback, which in turn can obscure low-level detail.

"Is this more of a solid state amp issue?"

In practice probably so.

David_ten: "How does it apply to tube amps with zero to very low negative feedback AND corresponding low damping factors?"

I would expect it to have all the low-level detail benefits of any other successful low-damping-factor amplifier.

David_ten: " Regarding:

I’ve had a fair amount of experience in driving the same speakers with both high and low damping factor amplifiers.

"Your generalized findings / results?"

First a bit of background: I design speakers with fairly high and unusually smooth impedance curves so that they have very similar response with both amplifier types across most of the spectrum, and then include user-adjustable bass tuning to adapt to the effects of amplifier damping factor into the bass region impedance peaks. So frequency response differences are minimal, and generally relegated to the region south of 100 Hz, where there can be a "free lunch" to the tune of an extra 1/4 to 1/3 octave extension with a low-damping-factor amp.

The following is my opinion; I can’t "prove" any of this.  Consider these to be generalizations; I’m not a writer of audio prose; and [disclaimer] I'm an Atma-Sphere dealer:

With low-damping-factor tube amps, I hear more of a sense of ease and liveliness and immersion. I’m hearing more stuff going on, it’s like the voices and instruments have more texture. Music is more engaging at lower sound pressure levels, which I think is related to the low-level details not needing as much SPL in order to be audible. At high sound pressure levels the difference is arguably even more noticeable, as there is an absence of the edginess which often starts to set in as the SPL goes up. I’m hearing more of a difference in soundscape and ambience from one recording to the next, with more of a sense of being "transported into" the recording, especially when it’s a really good one. There is a powerful emotional experience (some might call it spiritual) which some music can convey, but it calls for intensity and density and freedom from distractions. The least expensive amplification I have found which can do this is low-damping-factor tubes... specifically, the Atma-Sphere S-30 and M-60 [dealer disclaimer reminder].

Roberttdid wrote: " The example of the constant power amplifier as a tube-amplifier with transformer taps, is in my mind no different from the voltage amplifier paradigm presented... "

As a speaker designer I can tell you that the difference between the two amplifier paradigms is significant, whether or not output transformers are involved. The relationship between the impedance curve and the speaker’s output level differs depending on the amplifier type, such that if the speaker’s impedance curve has significant peaks and dips, it will measure and sound different with the two amplifier types.

Duke