Need cable to soften brightness just a little?

Would appreciate some hand holding on solving a small problem. I think a different cable interconnect might be what I need. Right now I am using Blue Jeans interconnects.

Have three new variables in our TV Stereo system.
New Oppo UDP-205
Musical Fidelity A3cr Preamp
Pioneer SX-1050 Stereo Receiver (bypassing it’s preamp)

Still in use is the Arcam SR250 AV Receiver.
Speakers are floor standing Spendor FL-6.

I am an opera lover and classical music devotee and like really good audio. The Arcam SR250 is just perfect for ordinary tv watching, but I soon found out it can’t equal the musicality of a good stereo receiver, so I rigged up a way of using my Audiomat Arpege tube amp for musical program listening.   But  I just found a better use for the Arpege and decided to replace it with the Musical Fidelity Preamp and the Pioneer Receiver.   The Oppo is just a few days old as well, replacing an Oppo BDP-83SE.

There is a big improvement in clarity of spoken dialogue.
Everything sounds brighter and clearer and there is an unmistakable sense of power from the much more powerful Pioneer.
Musically it is harder to evaluate. At first there was a feeling of “wow, major improvement”, but on further listening it feels a little bright. Might be the sort of brightness that causes music fatigue.

How do I take just a little of the edge off the brightness without losing the wonderful clarity I’m getting?

And how to go about figuring out which of the three is causing that little bit of edginess.