recommendation for speaker wire to soften the highs if possible


Hello,
I need help. My problem is my system sounds harsh on the highs to me. Not extremely bad, but enough that I need to fix it. My system consists of Ryan 610's, oppo Sonica Dac, and a Belles 150a hotrod amp. Speaker wires being used are old monster cable from the 90's. I also have monster cable rca. I mostly stream through Tidal. My question is can I make the desired effect by switching cables or should I add  a tube amp or pre amp. My budget on the wire would be around 300.00
Thanks in advance for any suggestions
128x128gunmetalzin
Sorry to disagree Geoff, I used ferrites for years on a variety of CD player RCA output wires to good effect. I have no problem recommending them to someone searching for a way to cut HF garbage from the speakers due to digital grunge... when they are looking for a low cost solution. The fact is $12 to discover if it is a worthwhile TRADEOFF in their system is DIRT CHEAP and may be all the need.Plus, as you mention, the ferrite may be good 'anyway' on AC cord.
Lizzie, now that your system has matured, and you’ve added a lot of new wall plates and other stuff, do yourself a big favor and remove all ferrites from the system. Then listen. Even better put all the ferrites on appliance power cords, fridge, computer, TV, etc. Report back. 🤗
That is were the ferrites are NOW. Frig cord, air cleaner cords, lamp cords, fans cords.. I took them off the CD player RCA cords at least twenty years ago. (But still some on captive CD spinner AC cords) TV is on the Furman REF20i  and uses a Pangea powercord. No need for ferrite there. Laptop cords have them built in...           
So do some aftermarket high end power cords.
If you wish to just try new cables I suggest starting with interconnects not speaker cables, they are more important. After that speaker cables.
How can you be sure that Monster speaker cables cause it ? It can be anything or everything.
+1 Many years ago, I reduced the majority of the digital HF grunge in my rig by cleaning up the power to both the modem and the streaming source. It had nothing to do with the speaker wire I was using.  And I had a tube preamp & amp.