I had this exact problem about which I posted a month or 2 ago.
In my case, not only did I have the wild woofer pumping, but also not enough gain from my phono stage.
I tried isolation first, no improvement.
Then I tried a much better and more expensive turntable, arm, cartridge solution. Still, the woofer pumping persisted.
Ultimately, I fixed the issue with a new photo stage, both with more gain AND a rumble filter. The latter is inaudible BTW, other than resolving the woofer dance while spinning vinyl.
Hope this helps!
In my case, not only did I have the wild woofer pumping, but also not enough gain from my phono stage.
I tried isolation first, no improvement.
Then I tried a much better and more expensive turntable, arm, cartridge solution. Still, the woofer pumping persisted.
Ultimately, I fixed the issue with a new photo stage, both with more gain AND a rumble filter. The latter is inaudible BTW, other than resolving the woofer dance while spinning vinyl.
Hope this helps!