Duck Walk W/O the Quack Please ...Blues Junior Help

[TerryD]

I have two nice tube amps.  A Stinger Delux Reverb Copy that is very nice and has a midrange control.  I also have a Blues Junior.  I did the bias mod.  I also have a Cannabus Rex speaker in it.  It also has a midrange control

I'm not that slick but can do some things.

In any case. I get more of a nasal type of a quack out of all my guitars running through the blues junior than the Stinger.  I don't like the quack.  I ran the opposite speakers to each amp to see if it was the speakers and that's not it.  In my thinking, I could next mess with the values of the midrange pot on the Blues Junior to get rid of the "quack".  Does that sound right?  Any help would be appreciated...any ideas?

Thanks Terry