Best tonerarm match for Acutex M320 III STR cartridge


I have lately been having feedback problems with using the bespoken Acutex cartridge in my Dynavector 501 arm. It sounds spectacular until the feedback sets in.Usable information on what tonearm might be a good (or bad), match is not easily found. The tonearm is mounted on my heavy plinth, with my Garrard 401 'table. It sits on a wall mount stand, Brightstar BigRock 2 sandbox, with Edensound large brass footers, that are six pounds each. 

My phono stage is a Modwright SWP 9.0, that has a resistor installed to cut low frequencies. One other factor is a 15" subwoofer that is about 10 feet away, that might be a factor.

Any information would be greatly appreciated.

Thanks, and regards,
Dan
Ag insider logo xs@2xislandmandan
Hello to the good folks that have posted to my tonearm/cartridge thread. I am now on a mystery quest, as I haven't been able to repeat the conditions that caused the feedback to occur. I have tried with the subwoofer on and off with both my tube amps, no feedback. The only thing left is to try using my Class D Audio amp. It's rarely used when I play vinyl, so that must be the culprit.

Anyway, thanks to you all for your help, regards, and Happy New Year,
Dan
For what it's worth, yes, my Lenco is in a slate plinth.  It is further modified in many other ways.  You could say it is a custom turntable that uses the Lenco motor, idler arm and wheel, and platter, and even the platter was treated so as to deaden any tendency to ring.  If you need further details, just ask. Happy New Year to all.
Dan
There is one more possibility and its so obvious I am sure you have already done it but.....

Maybe it was just one or a couple of particular albums?
You have played the same albums that you noted the feedback on?

If not this then it must have been the phase of the moon or a solar eclipse or them pesky Gremlins again!

Happy New Year!