I can't agree with the statement above that "Most" present amps use less global feedback. Compared to 20 years ago, yes. Now? Hmmm. For instance, the well respected Parasound JC-1's use 39db. Most would consider this moderate. ALl of the amps you have listed use a considerable amount of NF, both global and some local.
The only amps using NO neg. feedback are the Theta's, Ayre amps and just a very few others. Ayre uses no feedback period.
FB amps do control the bass better but that's about it for sonics. The no FB amps are a little lighter in the bass but more pristine and correct sounding through the mids and highs. NF causes timing issues in the time domain. You are inserting the output signal back into the signal path 180 degrees out. That's a pretty big trade off for what you get but it's also a cheaper way to get a sonically impressive sound for most audiophiles and easier to manufacture.
No, NFB amps aren't for everyone but what is. Each has to decide what is more important to themselves. I find the no feedback amps more to my liking but I also had a Belles amp that had feedback, ran in class B and used Mosfet ouput devices. It sounded very, very good. So, I would have to agree somewhat with the implementation theory. Amplifier design hasn't change much over the years. Most improvements are in literature, from people who own them and but most of all---parts quality and consistency. Look at any amps basic schematic and it looks pretty much like it did 25 years ago!
The only amps using NO neg. feedback are the Theta's, Ayre amps and just a very few others. Ayre uses no feedback period.
FB amps do control the bass better but that's about it for sonics. The no FB amps are a little lighter in the bass but more pristine and correct sounding through the mids and highs. NF causes timing issues in the time domain. You are inserting the output signal back into the signal path 180 degrees out. That's a pretty big trade off for what you get but it's also a cheaper way to get a sonically impressive sound for most audiophiles and easier to manufacture.
No, NFB amps aren't for everyone but what is. Each has to decide what is more important to themselves. I find the no feedback amps more to my liking but I also had a Belles amp that had feedback, ran in class B and used Mosfet ouput devices. It sounded very, very good. So, I would have to agree somewhat with the implementation theory. Amplifier design hasn't change much over the years. Most improvements are in literature, from people who own them and but most of all---parts quality and consistency. Look at any amps basic schematic and it looks pretty much like it did 25 years ago!