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So Weird- No Stylus Contact Woofer Pumping with Hana ML and Elac PPA-2

I observed the weirdest thing I have ever seen in audio. With the cartridge positioned above the record, tone arm locked up and platter spinning, the woofers were pumping on my system. I googled every permutation of query I could think of but came back with no hits. That’s when I decided to video the problem- link below:

Mystery Woofer Pumping

I could type out all the details but the video pretty much covers everything. I thought ya’ll might be interested in this.

 

mitchellcp

Showing 2 responses by rhljazz

rhljazz
1,249 posts
 

I would be inclined to take a small magnet and run it over the platter to see if there is some point of attraction within the platter itself.  Simple test to do.  Very odd problem indeed.

rhljazz
1,249 posts
 

One or several  points on the platter that are magnetic, not the whole platter.  The effect would be a similar to a Hall effect sensor.  Your MC cartridge is acting as the pickup.  Yes, the platter needs to rotate to make it work.  I’d venture a guess that you would see the woofers pulsing just by turning the platter slowly by hand.

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