Have you thought of putting the turntable on a shelf mounted to the wall? That's what I did when floor vibration was affecting mine. At that time (20 yr ago), Target made a reasonably priced wall shelf.
Need help
A little back ground I moved from WV to Texas in WV my system was in a finished basement now it’s on the second floor of our home. My system is Rega RP 3 turntable with the Rega upgrades. Exact cartridge. Rega Apollo CD player Rogue Metis pre amp and a Carver MT 1.0 T MK lll amp. Speakers are a pair of Source Technology 7211’s with two Source Technologies HV/S 10/500 Subwoofers. Now my problem when I play a CD or listen thru head phones everything is fine. But when I use the turntable the subs go crazy vibrate the floor bad I can’t turn up the volume at all. Turntable thru headphones is fine. When playing a CD subs are fine. Just when I play a album. I’m not a fan of CD’s so I’m going crazy. The subs are 7 foot apart and the closest one to a wall is 42”. Thank you in advance for any help ideas of what I can do.