Do I esentially have a class A amp?

Kijanki, Could you translate the paragraph you wrote into English please, particularly the phrases framed with double astericks (**):

"Such amp will have 0.5% THD and perhaps only 50kHz bandwitdh not to mention **relatively high output impedance.** THD distortion is not that audible, 50kHz bandwidth is passable and **output impedance doesn't matter because inductor in series with the woofer is about 0.1 ohm (limitting DF to 80) while speaker impedance (being source impedance for back EMF) is mostly resistive.**

Thanks

NFB lowers output impedance. If amp has 10x higher gain before applying of NFB then feedback will lower output impedance tenfold. We call it 20dB feedback. As a result deep NFB some amplifiers end up with output impedance of single milliohms. There is no need for that, since inductor in series with the woofer is about 0.1 ohm, while the fact that speaker's internal impedance is mostly resistive limits even more. When speaker's coil moves in response to signal it also generates response (back EMF) that works like brake that limits coil movement. This brake has damping effect on the membrane.

DF=1000 looks good on paper but it doesn't make big sound difference. Deep NFB used to achieve it, on the other hand does, making sound bright and unpleasant. Highly praised Atmasphere amps have output impedance in high ohms (DF=1).
Some speakers work well with low output impedance amps while others, (overdamped) sound great with tubes, but sane level of DF is perhaps 100.

It is very tempting to improve specifications with NFB because it doesn't cost anything. If you see fantastic spects in cheap amp you know that something has to give - it is sound.

Kijanki,
Bravo! What you wrote has been confirmed by many who simply use their
ears. Those supposedly impressive specifications made possible with
increasing NFB don't result in high quality sound IMO.

Charles1dad, Thank you. Atmasphere mentioned negative effects of NFB many times. I still believe that shallow NFB can be used but design has to start with good circuit and quality components. The best is perhaps not to even think of it and just to listen.

I believe that most of us would agree that after a given point; a specific specs numbers can become irrelevant, academic, out of context or just marketing tools. On the other the other side of that given point; specific specs numbers can indicate appropriate or inappropriate system matching or just plain inferior design, manufacture or current operating status. And (the relevancy of) those given points of those specific spec numbers can change as the other spec points in the equation change. Before stating things as absolutes, I suggest we remember the context of the specific specs in the overall equation, when we can, and be mindful not to throw the baby out with the bathwater.