Do you primarily notice this problem with only the CD or does your TT give you the same appr effect ? Given the fact that you are using a Grado, i would venture to say that it is primarily a CD based problem.
As to the comment about changing speaker cables, most Monster designs tend to roll off high frequency information. While changing to something else might increase system resolution and reduce some of the high frequency grain, i fear that it would also increase high frequency content. Obviously, this would end up making things even worse.
My next guess / suggestion is that the problem is probably related to your preamp. You stated that you've had this same situation with different amps and sources, so the only active component ( other than speakers ) is the preamp. The fact that this preamp dates back to over 20 years ago tells me that it is probably in need of a major tune-up or replacement. Most SS gear from that time period tends to sound hard, smeary and bright. Combine that with a metal domed tweeter and you may never get rid of the problem.
While there are ways to "band aid" the situation by changing cables, placing felt rings around the tweeters, etc.., i would check into trying another preamp if at all possible. Hopefully, you have an audiophile friend or dealer nearby that would be able to accomodate you. Sean
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