Denon DL-103 -- Was it a mistake?

No way a properly set up, sound DL103 is either bright unmusical. Something is amiss. Your impressions are the exact opposite of what the DL103 is known for, and what I've experienced for sure.

I wouldn't recommend any cartridge to anyone unless they had a properly matched tonearm. In fact, it's borderline irresponsible to post what mounts to a negative review of a product based on improper use.

As a matter of psychology, at least some people will take away a negative impression of the DL103 from your reported dissatisfaction with it, despite the disclaimers that you didn't have it set up properly. That's why I think it's borderline irresponsible even to report on it. I's like spreading an unsupported and unflattering rumor.

That it doesn't sound good on a mismatched arm is absolutely no strike whatsoever against it; how it sounds on a mismatched arm is irrelevant to how it sounds properly set up. So why did you bother to report this, and reiterate it even after it was clear the arm was inappropriate?

No I'm not. I think it's constructive to point out when someone is erroneously acting as if he or she has reasons to think there may be something amiss with a product -- especially one as widely admired as the DL103. Just what constructive point is there is stating that a cartridge badly set up doesn't please you? hey folks, I think prime porterhouse steak just as good as everyone says; I burnt one up well done, and it was dry and flavorless!