Is it too bright or is it high resolution?

One must wonder if a "to bright" presentation may be the result of harmonic distortion. Whether this is an amplifier issue a preamplifier issue or the interplay between the electronics and speakers. I am certain that we all want all of the details without undue brightness.

Trace amounts of higher ordered harmonics cause brightness as the ear converts distortion into tonality. It also uses the higher ordered harmonics to gauge sound pressure (rather than fundamental tones) and so is more sensitive to them than modern test equipment.

PHD
 When you inserted the CJ pre amp
 Did you invert the polarity at both speakers?
           

@stringreen re the difference between brightness and clarity you are spot on. Your definition of clarity lines up exactly with what I got adding a super-tweeter to my system -- definitely not 'bright' but much more insight into the recorded space and the different elements of the performance -- more details on my experience here 
https://forum.audiogon.com/discussions/supertweeters-yes-please

audioconnection, not at first because I was unaware that the CJ preamp inverts phase. But I did recently invert the polarity to the speakers and it now does sound different on most CDs. Thanks for your question.

The subjective term "bright" or "brightness" relates to the high frequency content of the sound source.   It's a fact that human hearing is most sensitive to sound between about 500 Hz and 5000 Hz.  Above and below that range the human auditory system falls off sharply and varies greatly one person to the next.  That is to say we all hear differently which leads to the wide range of opinions on what sounds bright or dull and so forth. To further complicate matters, our hearing changes throughout the day, especially at higher frequencies.  To prove that point, listen to your sound system in the morning after a quiet nights sleep then listen again after driving home in your car after a days work.  It will sound different.  The electronics and speakers did not change, your hearing did.

When it comes to high end amplifiers there are certain differences that cannot be measured but can certainly be heard.  The classic example is tube amps versus solid state.  Tube amps generally sound warmer while solid state amps are regarded as brighter.  Again referring to high end equipment, the differences are small but they are there.  I currently own a pair of Audio Research Ref 610T's and a Pass Labs 350.8 and must admit I hear differences with identical music sources.  To me, some music selections sound better on one amp and others sound better on the other amp.  In general, my wife prefers the 610T's which to her ear and I agree delicate and revealing yet enormously powerful when needed and above all, easy to listen to.  The Pass seems to be a bit more punchy in the high end and harsher when pushed which may appear brighter but I don't think I would call it that.  Perhaps a few harmonics are added but nothing big to speak of.   So, problem solved.  I got two great amps and one great wife and all is good just waiting for the next great audio adventure.