To misquote Morrissey, some knobs are better than others. The Manley Neo-Classic 300B amplifiers that I've been listening to, for example, have a knob marked "feedback" that goes from 0 to 10. I've learned so much from using it that I've come to believe that if your amp doesn't have such a knob, it should. You see, the higher you set this control, the better the amp will measure. Applying more global negative feedback to these amps lowers their nonlinear distortion and noisefloor, increases their bandwidth, renders them less sensitive to the speaker's impedance variations and otherwise makes them more stable and efficient. In fact, by applying lots of feedback to an amplifier, it's possible to reduce distortion to barely measurable levels.
So what's the problem? Well, a few turns of the knob suggest that negative feedback isn't as useful as it appears on paper.
John Scofield: Uncle John's Band; Mort Garson: Journey To The Moon And Beyond; James Brandon Lewis/Red Lily Quintet: For Mahalia, With Love; Alan Ferber Nonet: Up High, Down Low; Greg Foat & Gigi Masin: Dolphin; Avishai Cohen & Abraham Rodriguez Jr.: Iroko.
Diskonife: Audible Spirits; John Coltrane With Eric Dolphy: Evenings at the Village Gate; Joe Henderson: The Complete "An Evening with Joe Henderson"; Matt Otto: Kansas City Trio.
Pet Shop Boys: Smash: The Singles 19852020; R.E.M.: Around the Sun and Collapse Into Now; Hot Tuna: Live at Sweetwater 1, Live at Sweetwater 2, Live in Japan.
Arne Jansen/Stephan Braun: Going Home; Joe Farnsworth: In What Direction Are You Headed?; Darcy James Argue's Secret Society: Dynamic Maximum Tension; Dave McMurray: Grateful Deadication 2.
Eva Cassidy: I Can Only Be Me; Dave Liebman: Live at Smalls; Ralph Towner: At First Light; Chet Baker: Blue Room; Various Artists: The Jazz Room, Vol.2.