What equipment upgrades or tweaks will improve the sound of drums?

Udog ...

The lower you get the noise floor, the better the percussion will become.

Better wall outlets. SR Blues perhaps?
SR Blue fuses.
Herbie’s tube dampeners
PPT Total Contact paste.
PPT Omega E Mats
PPT "Stop It" devises.
PPT "The Gate." 

If you do the above, you’ll be able to hear the springs rattling on snare drums and you’ll be able to discern in which direction the brushes are moving on the snares and cymbals. You will be able to hear the difference between vintage drums with animal-skin heads and modern drums with acrylic heads.

If you like rim shots, hard whacks, very defined bass drums, kettle drums, and percussion with dynamics to die for ... take heed in what I’ve posted above. Combined, these items will take your system to levels you have never dreamed possible ... without changing or upgrading any equipment at all.

Frank

millercarbon >>>

• "Seemed insanely spendy at first. But they sound so good the way I look at it now is I finally have records worthy of the system."

Spot on with the good copies. Tom Port of Better Records gets super-premium prices for his "Hot Stampers." I’ve heard plenty of them before they get to Tom. I have a good friend (Robert) who sells to Tom and he’ll bring them over to my place to play them here first. And sometimes, I end up with Tom’s rejects. Lucky me.

https://www.better-records.com/

Each pressing is so important in getting the best sound, even to the point that I know of collectors (me included) who will have two copies of the same recording because side one, for example, sounds better on one record, and side two will sound better on the other record. And in addition, there are so many recordings that sound better or worse from cut to cut. Same thing for CDs. Yes, we are down-right obsessed.

I wish you were close by. I’d love to dig deep into the vault and pull out some gems for you to hear.

Frank