"Norman Schwartz" wrote in message


I wasn't referring to problems purely related to sufficient volume
levels and the possibility of damaged hearing, etc..

OK

It appears to
be both true and generally accepted fact that listening via equipment
headphone jacks degrades signal quality at *any* volume level
setting.

The current context is headphone jacks on equipment that is designed
primarily for use with headphones. I gave a list of of equipment in the
first post you responded to Norman (you quoted the list!) , and this
description fits just about all of them.

Therefore a headphone amp is the way to go when using the
better Sennheiser's if you wish to take the most advantage of your
headphones.

Maybe it would be good to consider the technical differences between the
headphone jack on a piece of equipment that is designed primarily for use
with headphones, and those on a headphone amp, which is after all a piece of
equipment that is designed primarily for use with headphones.