@Rebbi, I have a VAC push-pull tube amp that has adjustable global feedback from 0-5 dB in 1 dB steps. The manual recommends trying them all as it is simply a means of matching the amp to the speakers. Sort of like trying various output taps or tubes.
I tried all 6 positions and found that my speakers sounded best with the 0 dB feedback. As I increased feedback, I noticed more high frequency detail, but at the expense of rhythmic bass drive. The music became thinner and drier.
Who knows? Maybe if I change speakers some feedback may sound better. It is all about amplifier-speaker interactions. I do think that it is a nice feature to have though, adjustable negative feedback, as it does allow for some wiggle room when matching amp to speakers. I wish more amps had this ability.
I tried all 6 positions and found that my speakers sounded best with the 0 dB feedback. As I increased feedback, I noticed more high frequency detail, but at the expense of rhythmic bass drive. The music became thinner and drier.
Who knows? Maybe if I change speakers some feedback may sound better. It is all about amplifier-speaker interactions. I do think that it is a nice feature to have though, adjustable negative feedback, as it does allow for some wiggle room when matching amp to speakers. I wish more amps had this ability.