That you changed speaker wires to the 4 ohm taps on your amp b4 replacing the tubes and heard a slight improvement does show component issue between speakers and amp and replacing the tubes should return the sound to what you're used to. ferrofluid drying up in tweeters is also very real and likely to affect sound before xover components wearing out. Listen to me acting like I know what I'm talking about, lol. You've been given a good lead to get your tweeters serviced and it might be worth it to you to be without your stereo the week or two just to have them tip top. Either way, good luck.
Midrange Increasingly Harsh
Lately I've noticed some harshness in the mid-range, especially with violins, clarinets and female voice. I recently bought a CD of female plainchant, and she hits the un-sweet spot so frequently I can't listen to it. I don't listen at high volumes, rarely over nine o'clock on the volume knob. The sound is not anything unnatural, just a less musical presentation and an unpleasant harshness.
I have twenty year old Forest Totems with their original cones, a Prima Luna Dialogue One amp which got new tubes about five years ago and an Arcam CD-73 which got a factory rebuild about three years ago. I have neither the money nor inclination to just start arbitrarily replacing parts, but would appreciate some insight and guidance on likely culprits.
Thanks,
John Cotner
New Ulm, MN