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.



Looks like something I saw recently. The guy was using a balanced cable from his table to the phono amp. Changing it to RCA fixed the issue.

If you can’t get it sorted out, I have a KAB rumble filter that would do the trick.  I am not using it any longer and I could give a good price on it. Food for thought. 

The stylus is not on the record. How could it be feedback? The hi pass filter is engaged on the phono pre. 

If TT is turned off, does problem go away.? If so then I propose that the spinning platter has some iron content and this is inducing a very low frequency signal in the cartridge which is then amplified and affects the woofers.

Haven’t heard about this problem for 20 years. I think it has something to do with DC on your AC line. Will have to wait for the experts to return from the Super Bowl tomorrow...

Also, cut and paste the following line into google:

Cause of woofer Pumping in your speaker

Thanks, I checked google- nothing for this issue. The issue being woofer pumping when phono cartridge is within 1/4” but not touching a spinning vinyl record.

Switching to single end puts a stop to the phenomenon. However the question remains- what’s this all about?

Sorry but you have to prove that balanced input makes a difference by reverting to XLRs and re- testing. Also, is the phono stage actually balanced or does it just offer XLR inputs? Also retest with vs without platter mat. Also, what platter mat? 

Has nothing to do with DC on the AC line by the way. DC is DC; has no frequency. 

Wow that's a lot of homework. As much as I would love to, I'm not going to re-create the thing I just got rid of without some possible explanation as to what was going on. It's working in single end mode and sounds really nice.

Phono stage is an ELAC PPA-2 and yes it has a balanced input option on input two. It's activated with DS 3&4.

I did the test with and without a platter mat. Platter mat only creates the pumping. Record with no mat creates the pumping. Platter with nothing- no problem.

Mat is a Funk Firm Achromat. 

I didn't say anything about DC on an AC line. (..........never mind)


Hey OP, goto the top of this page, where it says "search discussions..." and type in "pumping". LOTS of people had this problem.

BTW, have you ever heard of "clarity vinyl"? This is vinyl with NO black stuff included (clear vinyl). The reason it is clear is some feel the black stuff generates some kind of magnetic interference. If you're cartridge is super sensitive, it may be generating enough current to make the woofers "pump". Try your test using clarity vinyl.

PVC cannot hold a magnetic charge, though compounds used may be magnetized so to the question is whether this happens with all lps or just one.

I also have a Hana ML cartridge and I do have woofer pumping but only when the needle is in the groove. Do you have that issue as well?  I eventually installed a KAB subsonic filter and all is good. Just wondering if you found some other way to address that. 

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.  

What kind of table & arm?  With that nice cartridge, I’m guessing it’s probably a pretty good quality one but it seems to me that if this only occurs when the platter is spinning, it’s a mechanical / vibrational issue in the plinth / tonearm connection, /suspension components or maybe the bearing.  A relatively cheap stethoscope you can get from CVS can help to locate the culprit. 

The OP clearly stated and also shows in the video that he’s using a Yamaha GT2000L, a very fine vintagE DD  TT with a coreless motor. So far as I can determine that platter is all aluminum. Which is why I asked about the platter mat, wondering whether it might be ferrous. I know nothing about the Funk Firm, but I’m guessing it contains no iron or copper.

Post removed 

The video already answers most of the questions and discards most of the solutions being discussed, please take a look before making a suggestion:


Static charge is the best explanation yet. I use an AQ Anti Static brush but it didn't do much if anything.

@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.   

I would be inclined to take a small magnet and run it over the platter to see if there is some point of attraction within the platter itself.  Simple test to do.  Very odd problem indeed.

@mijostyn static can build up on one section of the vinyl. As the record spins the area with static affects the magnets in the cartridge and causes the base to move in rhythm with the section moving underneath the cartridge.

As others have said, it could also be a magnet on the platter used to read and calibrate speed.

If it was a magnet on the platter, the problem would occur when the platter had no record or mat. If you look at the video, you’ll see that does not occur.

I think it’s a red herring, meaning something else is or was going on that neither we nor the OP have detected. Which is why I asked the OP to see if he can recreate the phenomenon by restoring the original conditions. It cannot be the platter per se because we see the pumping disappears when LP and mat are removed. Funk Firm mat contains no metal either. I’d bet the pumping has either directly to do with balanced mode or has nothing to do with what we see.

I certainly don’t blame the OP for not wanting to change back to XLRs just for my/our benefit.

Maybe I can pick up some cheap XLR to RCA adapters just for fun and see if it repeats.

I think the problem is stored energy in the vinyl and the mat- either separately or combined. 

I’m not sure if an earth grounded chassis would help. This TT is not earth grounded. The motor power is a 2 prong feed from a 120/100 volt step down transformer. The native power being Japanese 100v 60hz.


   Could be something is oscillating in balanced mode but why would it go away when you removed LP and mat? Neither of which can “store energy” for more than milliseconds. And it would be kinetic energy, not electrical.

One or several  points on the platter that are magnetic, not the whole platter.  The effect would be a similar to a Hall effect sensor.  Your MC cartridge is acting as the pickup.  Yes, the platter needs to rotate to make it work.  I’d venture a guess that you would see the woofers pulsing just by turning the platter slowly by hand.

The platter is solid aluminum.  Even if it had a layer of another metal hidden below, it would be a solid circumferential piece. It makes no sense to invent possibilities that are very remote and then feel satisfied that you know what is going on.  And even more important, if you watch the video, the pumping ceases when the LP and platter mat are removed!!!  If the platter per se was the cause, that would not happen.


Just for grins-even though you don't want to undertake onerous steps-please try switching the neutral and ground wires at the clips. Should take you less than a minute. I am sure you know this-use your fingernails and not pliers. 

This one is a pickle, to be sure.

I wonder if this table has a signal cutout mechanism that detects when a record is on on or off the platter and shorts the output when there is nothing on there? My Dual 701 has a signal cut mechanism, but used differently - it cuts the signal when lifting at the end of a record or when auto-starting. The point is that some turntable manufacturers have thought to prevent outputs in certain conditions and Yamaha has done this with some of their tables. I don't know if they did it for this one. What are the two holes in the platter for I wonder?

You could test this without changing the interconnect plugs. Just put your stylus over the spinning platter and use a stylus brush to lightly touch the stylus (like you would be cleaning it) and see if it makes any noise in your speakers. Then do the same with the platter mat and record off and see it still makes noise when brushed. 


The two holes on the platter are threaded so you can attach a pair of removal bolts- it’s ridiculously heavy.

I’m voting on static buildup. The filth on your records is the tell. I’d be interested to check the humidity of your house, the carpet (or rug) between your record storage and turntable, what kind of shoes you do (or do not) wear, if you wet-wash or simply dry brush your records, etc. I’m assuming whatever you are doing before putting the vinyl on the platter is leaving one heck of a charge on your record. The other questions remain: Did the single ended connection really solve your problem?  Did the rewiring create a better ground path? Why do people feel the need to comment without watching your video?

@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. 

He’d have to reinstall the XLRs and switch to balanced mode on his preamp in order to revisit the problem, and he prefers not to do that. So further conjecture is futile.

Let’s review,

Woofer pumping is tied to rotation speed, the pumping is faster at 45 than 33 also spinning the platter by hand will excite the woofers.

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.

B1- Disproves the magnet in the platter theory. Also the platter is hot forged and is as close as humanly possible to 100% pure aluminum. There are no ferrous metals involved.

Static electricity is just that static, hanging on for as long as it takes to discharge to an object of lower potential. I believe it’s widely accepted that vinyl records are able to hold a static charge. So I’m all in on that.

@nrenter I’d be interested to check the humidity of your house-

25%RH right now.

if you wet-wash or simply dry brush your records, etc.

Wet wash occasionally, dry brush prior to use.

Did the single ended connection really solve your problem?


Did the rewiring create a better ground path?
Ummmmm... maybe? I just check continuity and move on.
Why do people feel the need to comment without watching your video?

I don’t know, it’s annoying.

@lewm The issue with the pumping occurred over a period period of days and the video shows only the effect and it’s current solution.

To me the bigger question is about the implementation of balanced phono output overall. I was pretty eager to try balanced output in my system for it’s obvious benefits, 6db boost over single end, inherent in system noise reduction etc. I was not expecting to see a whole new problem surface.

I would really be interested to hear from anyone with a balanced output system as to how their experience is going.

It’s possible this is one reason so few phono preamps offer this feature. I know Project has a whole program for balanced TT’s. If so, I’m guessing they have incorporated solutions to situations like this.

There could be a simple wiring fix to this.

I will be looking into static control and once I have some tools on hand, I’ll probably attempt the Balanced output experiment again.



@dweller , I had one of those when I was a teenager back in the late 70's, it's funny to see it again. So funny I'll have to buy one- again.

I also had a Zerostat in the seventies. Seems to me, it was four or five times stronger than the current ones. They used to use some kind of radioactive element which came with a warning to keep away from your children.