Anybody own a component that sounds better with the cover off?


I'm not a big tweaker at all but recently I've been figuring out a problem I've have with my Lamm LP2 and now that it's fixed I've been listening with the cover off and then on and then off again and it just sounds better with it off. Things just seem tighter sounding. More precise. 

I've gone back and forth so I don't think I'm imagining it. It's not like I'm putting crystal on top of the speakers or anything :)
dhcod
Stereophile's Jonathan Scull was beyond anything so crude as removing covers. He claimed to torque and align the screws for the best sound.   

Of course he also claimed to be perplexed by a change in his system until he realized the cleaning lady had vacuumed his rug so the fibers were going the wrong way. Never quite sure if Scull was blowing smoke, or just inhaling a little too deep.
Audio Research has experimented and changed their top and bottom plates for their non amp components a number of times moving from metal grates to the smoked plastic because they sound better.