Please Read and express your feelings and opinions....

"Each 2150 uses global feedback (proudly: its manufacturer suggests that manufacturers who don't use feedback simply don't know how to do so properly)" About the Boulder 2150 from Stereophile. Different strokes for different folks.

That isn't quite true- but it is true that many who **do** use it aren't administering it correctly. The problem (known since the 1950s- see Norman Crowhurst) is that feedback makes distortion of its own thru bifurcation of the signal- and so adds higher ordered harmonics and intermodulations interpreted by the ear as brightness and harshness. And no-one has sorted out yet how to get an amplifier to clip graciously while using it. Here is an excellent article regarding the application of feedback and its pitfalls, several of which don't get addressed in many modern designs (and its not an 'anti-feedback' article):

http://www.normankoren.com/Audio/FeedbackFidelity.html

I recommend reading all parts.

I've got a SIT amplifier right now (and not just a Sony VFET either). It is one of the best solid state amps I've heard. Its too bad this technology got binned before it really was understood.

👨‍🚀
gdhal
geoffkait - “No controversial audiophile tweak has ever been proven to be a hoax or a fraud. - old audiophile axiom.”

@geoffkait
Nor has the impossible ever been proven to be the possible. An old opportunistic axiom. 🤑

Whoa! Are you high? That’s illogical to the extreme.

A sufficiently advanced technology is indistinguishable from voodoo. That’s what applies here, obviously. 

"Can't we all just get along?"  

Anonymity in cyberspace is the breeding ground for all sorts of bad behavior including bullying and brow-beating.  Some forums and forum moderators run a tight ship; others not so much.  Methinks the governing thought is that we are all adults and should behave accordingly.  That doesn't seem to work out so well does it?  As someone mentioned, it is the nature of the beast.

Whether it is high-end audio, sports, hobbies, automobiles or your favorite food, everyone is entitled to their opinion - but one must understand and recognize that it is "their opinion" --whether it is based in fact or not.   We come from different cultural and educational backgrounds.  We all have something positive and constructive to contribute.  

Maybe a few ground rules are in order (as long as they are observed and enforced):

It's important to remain civil and respectful.  Agree to disagree.

Think before responding

Stay on point

Attack the problem - not the person

Educate not intimidate

Share. Enlighten. Have an open mind. But most of all, have fun.

I assume the discussion is concerning global negative feedback and not local feedback. My amps as well as several other major brands of tube amps use negative global feedback. VAC, one of my favorite major brands, states that their amps use 6 db of negative global feedback. The finest audio/music system I’ve heard is the VAC/Von Schweikert $1million system.  I suppose Kevin could have built the amps with no or less feedback, but his design works great with it.

My amps have four variable points of negative feedback which I use the minimum for most recordings (some bad rock CDs need more feedback to make them listenable for my wife). I’ve tried no feedback amps and am dissatisfied with their sound (they were also Class A type).