Strange subsonic rumble problem?

Hmm.... I have 2 arms on my TW Acoustic Raven AC, a Reed 3Q and FR 66S sitting on Minus K platform. Yesterday, I took out my Koetsu cartridge and put on Ikeda Kai on my FR 66s. After the usual setup routine, I noticed significant subsonic rumble with the woofers pumping like mad when using the FR 66s. No such problem when using Reed arm playing the same record. I never had subsonic rumble problem in my system for a long time now and no problem with FR 66s in the past. The setup seems to be fine, all the joint, screws, etc are tightened properly as far as I could tell. Overhang, VTF, VTA, etc has all been checked several times so I am out of idea now what else to check to eliminate the problem. I assume airborne vibration, acoustic feedback should not be an issue since the problem was not there before and the turntable sits in the same location for years now.
Thanks for any suggestion.

Showing 4 responses by sarcher30

That's strange. I would put the Koetsu back on that arm. If it there is no problem after that, then at least you know it's not the arm. Could be that the Ikeda Kai has a problem. Try it out on another table.
It could be tubes. I would contact Glenn at Aesthetix, and explain the issue. I'm sure he can help you figure it out.
Maybe that arm/cart combo does not like that record? Does it do it on other records? If so, you may have a problem with the arm.
Hmm. I guess it's just a bad connection. I would not think that would cause woofer pumping. Could be something is causing the preamp to go into oscillation? Maybe someone with more technical background could elaborate?