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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
dweller's avatar
dweller
3,754 posts
 

Have you tried putting the record on the metal platter (without the record mat)?

How 'bout the mat with no record?

At least you'll isolate the offending object.

mitchellcp OP
86 posts
 

Yes

dweller's avatar
dweller
3,754 posts
 

Results

mitchellcp OP
86 posts
 

as per previous post 

A- Pumping exists when the system set up is: Balanced output from tonearm to balanced input at phono preamp and:

  1. Stylus is over the play surface and the platter is rotating- not off to the side (it also persists with the stylus on the record).
  2. There is a just a record on the platter (rotating)
  3. There is a just a mat on the platter (rotating)- the mat is a synthetic material.
  4. There is a mat and a record together (rotating)

B- Woofer pumping stops when:

  1. There is platter rotation and the platter is empty, no record, no mat
  2. There is no rotation regardless of what on the platter.
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