Wide Bandwidth Amplifiers Problems

I don't know that is the claim at all. Seems to me it is pure blather you heard someone repeat and thought maybe they knew what they were talking about. This by the way covers the vast majority of what you are likely to hear. Pure blather repeated endlessly back and forth without ever a thought as to what is really going on.  

I'm not going into the weeds of what exactly is going on, other than to reiterate what I already said: radio waves are everywhere, every wire is an antenna. And add one thing: a tuner is a device that allows you to tune in to certain radio frequencies in order to hear them as music. Because otherwise it is just background noise. A tuner is deliberate. But you can accomplish the same thing quite by accident with almost any circuit. That is all that is going on here. Once in a while someone gets some really bad RFI. So bad they can hear a radio station. Then this guy, who has no clue why or what is going on, one of three neurons in his brain fires and he gets the bright idea, "bandwidth! It's the bandwidth!" Like Steve Martin, "Stay away from the cans!"  https://www.youtube.com/watch?v=eXRM3lFRwRI  

Wide bandwidth is good. You want wide bandwidth. What you don't want is a lot of misinformation from misinformed audiophiles who know just enough to be dangerous.

norany, What I said about knowing just enough to be dangerous? You just heard from the closest thing to that Steve Martin character you ever will find. Only, Steve Martin, "The Jerk" he played was funny. Only difference.

Some wide bandwidth amplifiers can go into oscillation when used with some speaker cables. This can be fixed by adding a zobel network to the speakers binding posts. BTW, there is no audible consequence for this inexpensive fix.

spacial-temporal resolution of the human ear is, as a pair, and to some extent individually: exceeds a requirement for a jitter free 200khz/20 bit reproduction in digitally based signals.... 

the amplifier tends to be the same. the seeming contradiction is a excellent sounding  tube amplifier that may only go out flat to 17khz or the like. 

the situation is complex, at best. clean non phase-shifted bandwidth and similarly important clean dynamics is helpful, regarding both being a specification involving an amplifier.

Yet... a tube amplifier can violate both to some degree and still sound good...