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.

Ag insider logo xs@2xkrelldog
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.