How close to the real thing?

Timlub, It looks to me like Fas42 places a lot of importance on soundstage and imaging. There are different types of 'distortion' that affect that- primarily of bandwidth. The better it is the more intact the phase relationships, which are what defines image location.

The ability of the speakers to 'disappear' is equally important to a system's ability to convince as is detail and tonality.

When feedback is applied to an amplifier, low level harmonic noise is injected into the output of the amplifier. This is nearly all high-frequency information. Now it happens that room ambiance in recordings is often also high frequency and is also low level. The result is that by adding feedback, the low level detail associated with room size can be masked by the harmonic noise floor that is present in the amplifier. In fact *all* detail below this level will be masked. That is why amplifiers that run little or no feedback often seem to have bigger, wider and deeper soundstages.

Hi Atmasphere,
Ok, no disagreements...Feedback reduces distortion and have seen changing feedback levels change the effects, no arguments....
I guess, what I am questioning is... Labeling Distortion as a catch all phrase. It doesn't work.

Hello Atmasphere,

Wouldn't such be dependent on the topology being used, Tubes react differently vs SS with regards to negative feedback
(local or global).

Class-D amps run a lot of feedback, "alot" and they don't have issues with sound staging and details, actually they are quite possibly kings of it, but do exhibit a grainy artificial sound IMO vs conventional amplifiers (class-a, a/ab)

Mapman, -- "not all distortion is necessarily unpleasant" , I agree with your comments 100%. And, there is definitely "nice" distortion, which is quite easy to do, and is a perfectly valid way of obtaining listening pleasure. One of my earliest high end experiences was listening to a dealer's highly tweaked in home setup, we are talking here of Goldmund Reference TT, Audio Research D250, Infinity columns: of course the playback on a selected LP was absolutely stunning. He didn't like CD, of course, but had a CAL, so I tried one of my "test" CD's. The experience was bizarre, sounded smooth and pleasant enough, but half the sound content had disappeared! My half reasonable setup of the time at home absolutely walloped his in terms of conveying the musical message on that particular CD.

So "nice" distortion works, but it is "horses for courses" ...

Frank

Tubes and transistors seem to act very similar to feedback. I've less experience with class D, but from what I am seeing there are several techniques of using feedback and some work better than others, so it would be unsafe to generalize that feedback works in all class D amps without increasing odd ordered harmonics. In some it seems to work well though.

Not heard one yet that images as well as I am used to but I've not heard them all either.