Hello. Google searches kept leading me here so I finally decided it's time to join the forums

You are not talking to a bass_guitar - haha, realized that after I created the username but o-well, heh.
Rig information: Mesa Boogie 400+ ? i think it's an 82' model.. not sure.. Anyways, I recently had a tinsel wire break off and blow my amp. 333$, 12 new tubes and a few other minor things fixed it blew a second time, then is when I found out about tinsel wires and tube amps. Thankfully after the second time it turned out fine. Just a few blown fuses. Back to the speaker, I brought it in to be looked at, the speaker tech says that the coil is blown too. I guess they press on the paper and if there is a grinding type noise it means the coil is wasted. I installed my EV 15" BX into my Mesa Boogie cab, ran the wiring the correct way, checked the Ohms - got a 6.1 and things looked good.
The speaker frequency range of the BX stretches from 30Hz to 4000Hz which is out of the EQ range on the 400+ My question is, can that cause a fuzzy noise when quietly strumming a string? To trouble shoot the problem I crossed the 'fuzzy low end noise' with another cab that I'm not familiar with, besides it being 8 ohm, and the noise wasn't there. Clean tone. The BX has very little hours on it and I don't
think I ever used it the wrong way.
Any insights?
Thanks