SET amp w/Neg feedback?

Almarro 318B has 6db of feedback.
The best bass I have ever heard from a SET.As reviewers have said it sounds far more like a 100 watt SS amp in terms of bass control.
A superb sounding amp in all other areas too.

Using or not using feedback is NOT just about marketing hype.It fundamentally changes the damping factor of an amplifier.
Most speakers will not work well with zero negative feedback ampifiers.This is especially true for speakers with low impedences-below 8 ohms[most modern speakers].This is an electrical fact.Adding some feedback increases damping factor and this in conjunction with using tubes able to deliver plenty of current[not 300Bs] will seriously improve bass control.
Of course some people like the looose and bloomy bass of zero negative feed back SETs-but it is not accurate.

Atmashere,
I am sure what you say is theoretically correct.
I have had the opportunity to use amplifiers with variable feedback.Experimenting with the amount of feedback is very interesting.Certainly too much detracts from the sound.Most noticeable is the collapse in depth and precision of soundstage when too much is applied.
However to my ears a small amount of feedback gave a much more controlled and natural sound than no feedback.
P.R.A.T. was much better.