I think we can work with these pieces on my end. The EAR uses 10db negative feedback, the rest all employ some type of NFB. If you examine the schematic of those tube amps you list even w/o obvious feedback there are loops inherent in the circuit I believe.
That is one aspect of amp configuration i cannot understand well. If your amp is cathode biased then there is a feedback loop through the bias cap. Do you have any info regarding that? The Carver sounds dry and bland through the Pi Theater 4's. No life not real musical.
The Luxman is a real ballsy amp but like all SS amps I have ever heard it sounds a little flat and two dimensional, although the class A SS amps are much more musical.
The Fisher is coloured but musical.
The Dyna ST-35 is very smooth and musical.
Same for the ST-70 except it has a slight mettalic tinge, although that may be the result of very high frequency oscillation.
The EAR is one of the best amps bar none but it tends to be less involving than some other good SE's.
Thats good so far my hands are getting tired, Thanks much for helping me out with this reviewing thing, J.R.( The chip amp is a great bargain but not for long term listening)