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

Everyone is focused on magnetism. This phenomenon is not magnetic. Something else is causing the cartridge to output a very low frequency signal. The cartridge is a very sensitive vibration measuring device. To output a signal all you have to do is move the cantilever. An unloaded cantilever hanging in the breeze might be sensitive to air currents. Blow gently on the cantilever and watch the woofers. For some reason the spinning platter with either the record or mat loaded produces an air current that the plater alone does not. Loading the cartridge differently by going from single ended to balanced configuration could change the damping on the cartridge enough to bring this out?

@mitchellcp , I also run balanced but other than blowing on the cantilever, I can not replicate your situation. 

Right. Is there a gain difference between balanced and single ended? Run a meter across the cartridge right and left channel negative terminals. It should be open. 

You said it pumped with either the record alone and the mat alone as well as both. It only does this when wired for balanced operation which floats the ground.  I assume you will maintain single ended operation so further experimentation would require rewiring the connectors again which is a PITA. I will bring it up with a few friends and see if they have any ideas.

I run balanced all the way and can not replicate the problem. May be time to call the Ghostbusters.

I wonder what would happen if you changed cartridges. Both the mat and the record elevate the rotating surface toward the suspended stylus. Every rotating surface has son "fan" effect and may air currents around the stylus and cantilever.

Put both the record and mat on the table. Using the lift what does stylus elevation do to the intensity of the pumping. With the stylus suspend over the spinning record carefully slide a piece of cardboard over the surface of the record holding on to it. What happens to the pumping. Air currents could be interacting with the unloaded resonance of the cantilever's suspension?             

@mitchellcp , I missed that part. Very interesting. Is it the stock mat? Did Yamaha put the magnet in the mat?? Take any old magnet and scan the mat with it. 

Right, you are using a Funk Firm mat. Take a movie of the pumping take the mat off and put it on up side down see and take another movie, see if the rhythm of the pumping remains the same. 

You might also check with Funk Firm to see if there is any metal in the mat. There could be metal fibers (steel wool)  in the mat to remove static from the record. 

@lewm , there may be a magnet in the control loop under the platter. Very common approach. One thing is for certain. It is either something on the platter or the oscillating motor. The oscillations are perfectly rhythmic at 33.3/minute. I seriously doubt the mat. Who puts magnetic material in record mats? If its the motor that would validate my feelings about DD motors.

@dadawada , No it is not static electricity. Static electricity would not produce a perfectly rhythmic motion. Static can also not cause induction because there is no current flow to create a magnetic field. Any path to ground would short it out.   

As you look at the video you pick up that the oscillations are rhythmic and that rhythm occurs at 33.3 times per minute. I think @ Lewm hit on it. There is either Iron in the platter or a sensor magnet that is inducing a voltage in the cartridge. That oscillation will cause distortion in the woofer. The solution is a less sensitive cartridge or a different turntable.