We are slowly getting better at understanding specifications and how to apply them. Specs are important no questions, but at the end of the day, we listen with our ears. If something is off in the listening experience despite good measurements, that's when the good engineers go back and ask why. Not my words, but paraphrased from Nelson Pass.

Keep 'em coming Lou! I remember the 70's quite well. At the time I was first getting into "stereo equipment" or "components". Like you said, the metric used at the time that was the alleged gold standard. At the time, the cutoff was below or above .1 - if the specs stated .0 anything, that was supposed to be indicative of good quality. It had nothing to do with sound or hearing...

Great video. I tried explaining this to Yamaha back in the 70's when they asked me how to improve their amplifier designs. Their over use of global feedback was one of the things I suggested they fix. Didn't listen.

THE A1...............my brother bouight one .......rarely seen such a nice builded integrated amp BUT whatever the volume setting the music NEVER came..........he sold it ! Overal NFB "always" messes up time realted harmonics , lowering the MEASURED DHT distortion on fixed frequencies static sine waves ...........and creating MORE distortion on low levels , low dynamic micro musical signals that are supposed to establish the reightfull tone of a voice, an instrument, an environment or a material identity ....that is called hard distortion and it is not talked about ! NFB works only correct in the real time domain , that's why triodes are so linear ( internal no time delay feedback ) ............ M%usic / sdounds are time related transients rather than thez proned frequency response in the audio world , in nature time is the prime capture of sound by the brain , precise location and distaznce od a sound source...........whatever the conditions of your ears and the loss by age ( or abuse ) ............;the identity and nature of the sound will ALWAYS be recognized ! ..............you will recognise the right time aligned harmonic structure of a familiar person or sound. Intermodulation is anotherr beast , it will ruin your perception of music ! The better system have low intermodulation even if the " classic " measurements of the DHT are not those of the high end audio systems and amplifiers or otherr components . Good music is instantly accepted by the brain , the soul and does not need analyzing or measured ..............you will not suffer from listening fatigue by those impressive sounding audio components ........listening fatigue is an indicator that something is realy wrong ! .....while specs are showing the opposite near to perfection ....... Most problems are problems with time perception..........altering the harmonic structure of natural sounds/music ... Thank you for the upload LOU.

I've not seen power band width in a while.