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

A Decca or London cartridge ;-) . No, seriously. I saw and heard Nigel live with EJ in 1971, and his Slingerland drum kit sounded similar to Keith Moon’s Premieres: big and boomy!

Duncan Browne + Simon Phillips "Streets of fire".
Find it on vinyl or YouTube.

Duncan Browne, a genius sadly died young, was the founder
of the group Metro that did a legendary first record.

I would be remiss by not giving a shout out to my New Dark Matter, the quicker picker upper. NDM eliminates both visible red and invisible infrared stray laser light in CD players in less than a picosecond. Restoration of bass frequencies is one of the primary benefits of NDM. I estimate 50% or more of the bass information and dynamics is simply missing in action due to the scattered light problem.

geoff kait
machina dynamica
we do artificial atoms right

:-) All you need is the right powerful speakers, I won’t tell you which, but you can guess!

@in_shore 

Hey in_shore. I just got off the phone with Tony Minasian and he'd like it if you could contact him as he has some music files he'd like to share with you. 

All the best,
Nonoise