Subwoofer rumble issue

Glad to hear you got it worked out and thanks for sharing the solution. 

Subsonic rumble filter! All better! I understand it’s a “bandaid” approach but it totally worked and my stereo sounds amazing again! YES!!! Thanks again everyone!

Yes until you figure out how to stop the airborn feedback, it is a band aid, as it’s taking away what stereo info there is below 140hz
Quote: "The circuit "monos" the low frequencies below 140 Hz"
I still don’t understand how this will fix the airborn feedback test I asked you to do though, did you try it again with this filter in place?

Cheers George

Yeah I hear ya. I also built an isolation platform out of two butcher blocks. I sandwiched it with gel furniture pad discs. I wonder if that is contributing to the solution more then the rumble filter. I’ll remove the filter when I get home and give it a shot. 

George - so I removed the filter and the rumble returned ☹️ even with the homemade iso platform. So even if I’m missing out on super low frequencies, it’s better than the earthquake situation. I’m planning on upgrading my phono pre so we’ll see if that does anything to alleviate the rumble like one guy said earlier. Thx!

Yeah unfortunately you have to live with the negatives of the rumble filter is doing to the low bass, shame as that was what getting a sub woofer was all about.
Like I said the only way to totally get rid of "airborn feedback" as you found you have with the way I said to test for it, is to have the TT in another room as I did and which worked a treat, best bass ever, as my 2 x Kef B1814’s in 2 11cu ft enclosures were tuned down to 19hz fs each.

Cheers George