Too much bass/feed back from Octave v70se

Hello all.  Has anyone experienced too much bass from an integrated tube amp? I just added  an Octave V70se to my set up. I've also added some room treatments. Which consists of cork wall tiles covering entire wall behind my system, and behind each speaker i have stacked a 24x24x5" bass trap with a 24x48" skyline diffuser on top of the trap and a 24x24" absorber/diffuser on top of that. The room is multi purpose so I did the best i could with the treatments.  My main set up is Anthem avr, bluesound node, anthem mca325 amp, rega p8, and a Schiit Skoll phono stage.  After the added room treatments I find that i listen predominantly with the ARC room correction turned off.  So the treatments definitely helped. 

  Now to the Octave.  I added the integrated tube amp because I wanted to mainly use it with my Rega.  I added a switch however that allows me to switch from the Octave to the Anthem so while I'm streaming through the node via my avr , I can switch to either amp.  The Octave is really really good. A noticeable improvement over the Anthem amp which I really like but at more than double the price it should be better.   Ok,  no problem there.  The problem arises when I run my Rega straight to the Octave via the Schiit Skoll.  Bass is very strong.  Too strong on alot of tracks. At about 50% volume i start to get what I'll describe as low frequency feedback it gets really bad the more I turn it up.  This dose not happen if irun the Rega through my Anthem set up.  My guess is that the stylus is starting to vibrate do to the bass. I have an isolation platter under the rega and iso acustic feet on Rega itself. Also isolationpucks under my speakers.  Which I forgot to mention are Paradim founders 120h. I also stacked some large cushions in the corner behind my right speaker.  The left one has open space behind it.  I've tried moving the Rega off of the council and further away but same thing happens.  Keep in mind that this is a no issue while running through my anthem rig.  The volume has to get pretty loud for the problem to show itself but as the volume goes up I starr to notice a slight LF noise which gets exponentially worse as the volume goes up.  Why? Can it be the tubes that make the Octave bass heavy?   The phono pre?  Is the Octave itself that sensitive to vibration?   Im at a loss.