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

@ejb14 

When you were spinning by hand, was the turntable power on?

No, when the power is on you have two choices, 33 or 45.

Powered items were amp and pre amp.

It’s kind of reproduced except mine needs a record or synthetic mat or both.

My oscillation hypothesis is officially in the toilet, if the frequency of the woofer pumping is equal to the TT rpms.  Over and out.

most likely this TT/Phone inputs w/o a grounding wire between them, so it is sensitive to 33 1/3 electro-magnetic  radiation.

It’s kind of reproduced except mine needs a record or synthetic mat or both.

So it pumps with a record and not a mat, but no pumping with just the platter?

 

 @byang12  I’m confused, could you restate that

There is pretty much electrical field and magnetic field.

I am having a hard time with an electrical field that is at 1/2 RPM… and a magnetic field should not be affected with just a piece of vinyl on top of the alloy platter.

It is either coming out of the cart itself, or it needs to be tied to the ground wire, like making some differential voltage between the ground and the cart, which is tied to the platter phase.
But those mechanisms should not be tied to rely on a mat or piece of vinyl.

I could imagine Lewm’s idea of electrical being tied into the electrical side.
@mitchellcp previously I think that you mentioned that there NO ground wire running to the electronics… and the PIn-1 is not tied to ground.

I am wondering if pin-1 should be tied to the ground at the TT end.