Bass distortion-Playing LP's only,,,,please help

VPI Prime----Ortofon Black Quintet (low output moving coil cart)-----Plinius Koru Phono Pre( loading at 20 ohms/gain at 66 db)-----Parasound Halo Integrated -----Martin Logan Montis speakers which have powered bass cabinets.

Using any other source component I have absolutely no issues. When I play an LP and increase the volume past 10 O'clock which is a little loud....but not ridiculously loud-I at times get this huge wave of bass distortion. I do have bass controls on the Montis's...and I have turned them down into the negative, but I still get what I previously described occasionally. 

Any and all help would be appreciated. This doesn't always happen, but its frequent enough to drive me crazy.

Thanks in advance.

If you decide on using the filters and you have no issues with other sources then plug directly into phono stage and then plug table into them.

+1 yogiboy

Looks like it will do essentially the same thing for a lot less money.  You have nothing to lose by trying these.

Scroll up and re-read lewm's post on 7-17.
Also check to be sure that your head shell is secure
Agree with most folks here - very likely acoustic feedback.  First choice of potential fix - move the tt further from the speakers.  If the speakers and tt both sit on the same suspended frame wood floor, this can be a bitch to eliminate.  If you can get them on two different flooring structures, you're way ahead in the game.  I know that's a big "if", but it's the best way to go whenever feasible.
Anvil turntable footers completely solved my acoustic feedback issues.  I agree with trying to move place your table farther from the powered woofers if possible. You never know how much better it might sound.