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Need help solving a system problem

The equipment:

Martin Logam ethos
musical fidelity m6si integrated
musical fidelity nu vista vinyl phono pre
EAT C Sharp TT with a Kiseki Purple heart cart.

The issue simply put:  when I rest the needle on the record (record not playing) and I turn the volume up to the 12 o'clock position, I get an incredible amount of woofer vibration from the logans.  Same issue when playing a record. 

I've tried:
1.  better isolation ...keep in mind record is not playing so acoustic feed back is out of question.
2.  Speakers are 43 inches from the needle when on record from each side.  tried moving to max distance room will allow to no avail. prob still occurred
3.  tried a different table with different cart.  got same issue.
4.  Upgraded stand ...isolation again.
5.  tried different tonearm cables, different inputs on pre...same prob.

Any ideas are welcome.  I love my system just cant play it loud....and sometimes I like it loud.
polkalover
viridian's avatar
viridian
4,184 posts
 
There are two paths for acoustic feedback, airborne, and structure borne. You may have a problem with one, or both.
oddiofyl's avatar
oddiofyl
1,076 posts
 
Good suggestion, so many receivers and amps USED to have rumble filters.   
4425
455 posts
 
if you use a rumble filter it needs to be really good as i believe the full signal passes. maybe dumb question but are there really good phono preamps that might have this feature? 
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cleeds
2,065 posts
 
tablejockey
ALL system's speakers will do the same with a table.
Not so. Feedback may be a common problem with turntables, but it is not inherent in all systems. My speakers are flat, in room, to below 20 hz. I have no feedback at any volume level, and my turntable sits remarkably close to one of the woofer columns. It's all about isolation and, imo, mass. 
stereo5's avatar
stereo5
2,766 posts
 
The KAB Rumble Filter uses all audiophile approved parts.  I run mine via the tape loop on my preamp and I hear no difference with it engaged or not, but it certainly stops all the woofer pumping.
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