Is this the same as zero global feedback such as a bat vk-500 and how many gain stages does the onkyo have, and do you think the older onkyo could compete with the bat,what amp would you chose, take a look at the link below and give me your opinions.

My browser said site did not exist so I couldn't find it. It is not the same. I remember the Onkyo as a good amp in its time, early 80s? It probably would not be competive with a good modern amp, altho it might be quite listenable with right equipment. The Zero Distortion is reminiscent of a Japanese obsession of the 70s and early 80s to reduce distortion to the lowest possible figure. They did this by using massive amounts of feedback, the opposite approach that is popular today. The result was some amps that measured well and were truly awful. They brought to mind Percy Walkers claim that he could design an amp that would measure well but would render music unrecognizable. The Japanese came close. That said, I don't think the Onkyo is one of those. The zero distortion was just a marketing slogan and ment nothing.
The M-510 is one of the greatest amplifiers ever manufactured. Its big powerful sound competes with any amplifier made today. The M-510's fit and finish cannot be duplicated. Have you ever owned one? Or ever seen one in the flesh? Its totally amazing.