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 :)
Yup. My phono amps have been topless since forever. Really noticeable with tubes. My LP12 was also coverless in the 80s. I've mentioned this as a great free upgrade in posts over the years.
Superphon space case.
With small kids at home I will never find out. 
pretty much any of the old style tube amps w cages, even the well executed e.g. Music Reference RM-9, Mac 240….

For those needing to retain the cover, i can highly recommend two different products: HRS damper blocks, VPI Magic Brick. There are others including DIY
Art Dudley would frequently comment that his Shindo tube gear sounded best with the cages removed.  
Art Dudley - RIP. Now that cat was the real deal
My Speakers sound better w/o covers
Years ago running Perpetual Technologies dac, Two very small enclosures around chassis, much better sq without enclosures. Haven't heard this with subsequent equipment.
I can hear my girlfriend much better with her top off. 
Really, I would think you would hear here better with her top on. 
One of my early vibration control lessons, dealer told me people like their Aronov amp better with the cover off. Sure enough, no doubt. 

This is almost certainly due to the elimination of cabinet ringing. These things all vibrate, that is why they sound better on springs. And they all ring, that is why they sound better with damped springs like Pods. Cabinets are a trade-off between sound quality, dust, and safety.
or just remove the cover (cost = $0).  And avoid buying springs and pods.
I leave my toilet lid off,and it works much better.
I owned an Audio Research SP-8 years ago that definitely sounded better with the top panel off. Probably could have stayed on if the right kind of damping material had been used.
This was first mentioned decades ago in The Absolute Sound, by Enid(?).  This might be why ARC has moved to plexiglass tops on their line stages.
@docknow Enid Lumley, A quirky visionary.
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.
Also mentioned decades ago by Mother of Tone.
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.
Yes; the Eastern Electric Minimax DACs that I have sound better with the covers off, because I have rolled into them discrete opamps. 

TT cover on/off———no difference. 

Change cartridge, ...adjust weight..... cover off/on - cartridges sound same with cover on or off,
I leave them on for convenience, and to keep in good shape, when things come off, get stored, scratches, cracks magically appear (PFM)

I just took the dust cover off my Linn Axis. It sounds better with it off. I think everything matters. You just have to decide how much. Is the juice worth the squeeze? On my system the answer is usually yes. I do agree with the storing of products. Things can get damaged. Also the costs to improve the sound. The costs of isolation products can really add up.  I have petrified wood bookends on some of my phono preamp, BlueSound Node 2i, and the to of my amp. They can handle the heat, definitely improved the sound, and they look good. 
If you really want some bizarre reading go to Mapleshade Audio and read his suggestions for good sound. One of them is never run gear with the covers on. Some of his stuff is out there but a lot of it works you have to let your ears decide.