Woofer pumping WHY??

You are getting rumble. You need a phono preamp with rumble filter. You can damage speakers without it. Too much acoustic feedback.....PT

Matt, when you play the records you referred to with the sub disconnected, do you see any visible indications of woofer pumping in the main speakers?

If not, it would seem likely that what is exciting the arm/cartridge resonance is not minor record warps, as is sometimes the case, but rather acoustic feedback from the sub. In which case some experimentation with sub placement may be in order. And possibly also with isolation provisions under the turntable, despite the statements in its literature about "perfect decoupling through magnetic feet" and a "mass loaded magnetic floating subchassis."

Also, while chances are it is unrelated to the problem (although it is conceivable to me that it might be), where are you connecting the ground (black) wire of the sub's Speakon cable? And does the sub have a 3-prong power plug? If it does, you should probably NOT be connecting the black wire of the Neutrik cable to a negative output terminal of the amp. And come to think of it, given the amp's "quad balanced" + autoformers design I'm not sure that the black wire should be connected to a negative output terminal even if the sub has a 2-prong power plug.

Sorry to hear, btw, that the sub may be damaged. But perhaps if the pumping issue is resolved it will no longer scrape.

Good luck. Regards,
-- Al

The tonearm mass is a low 8.5 grams ,the cartridge has a compliance of 15 (on the low side). That combination looks like a mismatch to me. You can try a headshell weight to add some mass to the arm and see if that improves the problem.

Get a KAB rumble filter for 189 and problem is solved. I had the same problem with my Scout turntable, I tried relocating the turntable to various locations and using all kinds of platforms under the turntable and nothing helped. Put the rumble filter on the tape loop and use it when playing records. All the oscillating speaker problems will go away. I hear no difference with the rumble filter in and out of the system. The only thing that changes is the woofer pumping: none with it on and all with it off.

I had a big woofer pumping issue

In my case we finally isolated it

The bearing in the tonearm wasn't moving properly so there was cyclic woofer movement as the cantilever took the brunt of the motion

We did a feather test suggested by Thom Mackris and that was it

A tonearm tune up and no more issues

One of my threads on it

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1400370649&read&keyw&zzwoofer=pumping

What is your flooring type, turntable rack / isolation?
Is it more apparent on the outside grooves of the record?
Is it cyclic or keyed to loud passages or bass heavy parts of the music?

Search engine is your friend

I found 8 threads putting in the words woofer pumping