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

@ejb14

1. Isn’t woofer pumping caused by infrasonic frequencies (below 20hz)?

Yes it is

2. The PPA-2 has a rumble filter and I believe that I saw it turned on when the woofer pumping is occurring - doesn’t a rumble filter filter out these frequencies precisely for this reason - to prevent large woofer excursions?

The weird thing is that the hi pass filter works, I have some real nasty LP’s that rumble and the filter knocks it out. So your guess is as good as mine. Also the pumping was worse with the filter off- real audible bottoming out stuff.

3. Not sure how static would cause the cartridge to output signal in the infrasonic range. Even so, the Funk Firm mat claims to be static free, yet with just that mat on the platter still exposed this issue; so if not static, then what?

I’m still all in with team static, until a more likely explanation is revealed or Peter Madnick see’s this and can explain it.

70% of people are stupid. Fortunately, I'm in the other 40%.

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?             

@mijostyn take a look for yourself 

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.