Hello Captain,
I'm delighted you solved your M80 problems, no thanks to the Bose "subwoofer". It was really bothering me that you weren't getting the stunning performance the M80s are capable of.
By the way, I love Capriccio Espagnol and lots of Rimsky-Korsakov. If you like that, you'd likely like Capriccio Italien by Tchaikovsky, which has lots of percussion and rythmic drive. I first had the latter on vinyl in the late '50s, with Dorati conducting the Detroit Symphony. It was also on Mercury. I've never replaced it on CD.
Some of those 1950s recordings did suffer from occasional tape saturation on orchestral peaks, and that can't be removed by re-mastering. I doubt that is what you're hearing as breakup but there's an outside chance it might be. You could verify that if you have a good pair of headphones and listen to the same passage on the headphones with the speakers muted. If the breakup was in the source material, you'd hear it on the headphones (this is assuming that your old Denon doesn't have preamp overload on the input). That's also a stretch, but I've seen it happen occasionally.
Regards,
Alan
