What exactly does "zero feedback" mean in an amp?

[stubzor]

and in what way does it effect the sound signature? On one website its a good thing, another one claims it creates noise in the background. That would be great if i could get some insight.
 

 

[El_Doug]

Negative feedback circuits:  http://en.wikipedia.org/wiki/Negative_feedback_amplifier
 
When an amplifier is touted as having "zero feedback," it means that there is no feedback circuit in the amplifier.  This typically also means, by extension, higher distortion. 
 
 
Many, including myself, see negative feedback (used properly) as an invaluable tool that benefits the performance of an amplifier.  Others see any extra circuits in the system as "destroying the purity of the signal," whatever that is supposed to mean. 
 
 
You most often see "no feedback" in OPT tube amplifiers, where it is possible to not rely on feedback.  Even in these amps (imho), feedback benefits the sound.