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

Good find, Dekay.  For a true balanced hook-up from cartridge to a true balanced phono stage, audio ground is typically floated (no ground, in other words).  Pin2 of the XLR connector is typically connected to the positive phase ("hot" on an RCA connection), and pin3 carries the negative phase (the outer barrel of an RCA).  Pin1 can be connected to shield but not to the cartridge. Maybe there is a wiring problem that only pertains when operating in balanced mode. But I hate to say this, the video shows the problem goes away when LP and platter mat are removed, even though he is still (I think) operating the system in balanced mode at that point. If we can throw out that bit of information, it makes more sense. (Just kidding; we are stuck with the facts of the matter.)

Wiring for the tonearm to the preamp was as follows:

• Pin 1- no connection
• Pin 2- + positive
• Pin 3- - negative
• Shell ground- cable shield

Why was it wired like that? I agree the typical connection is pin 1 for the shield. See excerpt from the Elac PPA-2 Manual:

"Typically a balanced connection will be more immune to hum, so it would be the preferred connection. However, you must be careful that the shell of the XLR is not connected directly to the ground line within the XLR connector ( That sentence is a little confusing but I take it to mean that the shell of the XLR should not be connected to pin 1). They SHOULD be independent. The shell is the external shield of the cable and connector, and should be the CHASSIS connection. The ground wire within the XLR is twisted with the (+) and (-) balanced and should be the signal or tonearm ground. This can all be confirmed with an Ohm meter. "

The PPA-2 has two ground lugs, one for tone arm ground (labeled ground) and one for chassis ground (labeled chassis). Since there is no chassis ground on the GT2000, that lug remains unused. The tonearm ground is connected via the other ground lug.

The cable shield is NOT connected at the TT end, but is connected via XLR shell to the chassis ground.

Uh, see my previous post. You can still try it and report back. I suspect the problem goes away when you remove either the record or record and mat because the spinning magnetically charged item (record or mat or both) excites the improperly connected cartridge whereas the aluminum platter does not.

@fsonicsmith I thought that if I got continuity from cartridge white pin to XLR L pin 2, blue to L pin 3, red to R pin2 and green to R pin 3, and if George Cardas welcomed to the right channel on the right side and in phase was in the middle I was pretty good. What did I miss?

Have you tried putting the record on the metal platter (without the record mat)?

How 'bout the mat with no record?

At least you'll isolate the offending object.

Yes

Results

as per previous post 

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.

Any way this could have something to do with the 6db boost in balanced configuration compared to the single ended?  Does the woofer pump in balanced mode if the speaker is much farter away from the table?

Take a look for yourself

A few questions;

1. Isn’t woofer pumping caused by infrasonic frequencies (below 20hz)? A John Atkinson quote from 2009 Stereophile seems to support this, though he was referring to record warps in that quote;

https://www.stereophile.com/content/bass-cone-flap-1

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? If so, it would seem the rumble filter is not working on this phono stage - you may want to look into a warranty repair if we can assume the woofer pumping is being caused by infrasonic frequency.

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?

OP - Thanks for your indulgence. Think I may be developing ADD in my old age (turned 70 in Jan). Totally missed your original post.

As for the problem, damn that's weird! Got to have something to do with static elec/low humidity.

Thanks again. 

Attention Deficit Disorder? You’re probably just noticing it because you weren’t paying attention before.

@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.

Finally!! Someone who runs balanced!! Did you read this?

excerpt from the Elac PPA-2 Manual:

"Typically a balanced connection will be more immune to hum, so it would be the preferred connection. However, you must be careful that the shell of the XLR is not connected directly to the ground line within the XLR connector ( That sentence is a little confusing but I take it to mean that the shell of the XLR should not be connected to pin 1). They SHOULD be independent. The shell is the external shield of the cable and connector, and should be the CHASSIS connection. The ground wire within the XLR is twisted with the (+) and (-) balanced and should be the signal or tonearm ground. This can all be confirmed with an Ohm meter. "

I did not connect the tone arm ground to pin1. The tone arm to preamp cables are shielded star quad, so there isn’t an available wire from the arm to run the tone arm gnd. That's running externally, like a regular turntable cable. The shield ground is connected to the shell at the preamp end and floats at the other end.

That’s my deviation from the manual and although I doubt that is the issue, my doubts generally have no effect on the real world.

What do you think?

Has anyone here read the OP’s previous thread?

What is your point here @deKay?

It is almost surely a magnetic field.
I would do the test with the mat alone, and the record alone, but cannot fathom a mat being magnetic, however the fridge magnets are plasticy.

One could put a mark on platter and mat, and then try the mat at a few phase angles.
Or get a new mat, or degauss the current mat, or put a blocking capacitor somewhere.
A new mat is what I would suggest

A capacitor does not “block” a magnetic field.
but that’s not so much of a problem, because there cannot be a magnetic field generated from the Funk Firm Acromat, because it is completely non-metallic, let alone non-ferrous. (See the FF website.) I know there are some who believe that records can become magnetic and need to be degaussed periodically. I am not one of them, but even if it were so then we would all be having this kind of problem, and we don’t. Furthermore, a magnetic LP would attract the magnets in a cartridge, and could be disastrous for the suspension, but that doesn’t happen either. Furthermore, if LPs could be magnetized, they would become uniformly magnetic; the magnetism would not be patchy across the LP circumference so as to cause the phenomenon the OP observed.

As I said above and still believe, I think the story that goes with the observation (removing the platter mat and LP cured the problem, etc) is a red herring. If the phenomenon was to be further investigated, in other words, all that bit would be seen to have had nothing to do with the actual cause. For example, it is possible that the phono stage has the potential to oscillate at a low frequency when in balanced mode. Such an oscillation can easily be a some time thing; in other words it comes and goes. In the story, the OP had to shut down the turntable to remove the platter mat and LP. This might stop the oscillation that is really going on in the preamp, just by chance alone. When he switched to SE operation, that too would require shutting down the phono stage, and it could easily be the case that the premp does not oscillate at all in SE mode. If you have ever tried to chase down and cure an oscillation in a piece of audio gear, as I have done, you would know what a royal pain in the arse it can be. Took me over a year with an amplifier, and that was with help.

@lewm  You appear to be under the impression that everything I tried with that problem was shown on the video, that I just happened to be shooting a video as I was listening to records, as we all do, and shared this comic little problem because I'm off my meds.. 

That is not the case, what you see in the video; for you, the first time, was for me the umpteenth time. It was a problem that persisted over many hours, restart cycles, wiring checks, different records, different mats, disconnections and reconnections. If it's a red herring, it's extremely reliable.

Once I realized it was not going to go away, I shot the video because just explaining it in writing would stretch credibility past any reasonable point. 

@mitchellcp

Have you noticed any movement of cantilever during woofer pumping?

That with your balanced connection.

A capacitor does not “block” a magnetic field.

__ ____ Sherlock… but it blocks 33-1.3/60 Hz, as well as DC

but that’s not so much of a problem, because there cannot be a magnetic field generated from the Funk Firm Acromat, because it is completely non-metallic, let alone non-ferrous.

Those fridge magnets are also plastic.

(See the FF website.) I know there are some who believe that records can become magnetic and need to be degaussed periodically. I am not one of them, but even if it were so then we would all be having this kind of problem, and we don’t.

Agree

Furthermore, a magnetic LP would attract the magnets in a cartridge, and could be disastrous for the suspension, but that doesn’t happen either. Furthermore, if LPs could be magnetized, they would become uniformly magnetic; the magnetism would not be patchy across the LP circumference so as to cause the phenomenon the OP observed.

As I said above and still believe, I think the story that goes with the observation (removing the platter mat and LP cured the problem, etc) is a red herring. If the phenomenon was to be further investigated, in other words, all that bit would be seen to have had nothing to do with the actual cause.

The OP could for an instance use a compass to see if it has the periodic needle jiggle. Or hold that mat next to the compass.

For example, it is possible that the phono stage has the potential to oscillate at a low frequency when in balanced mode. Such an oscillation can easily be a some time thing; in other words it comes and goes. In the story, the OP had to shut down the turntable to remove the platter mat and LP. This might stop the oscillation that is really going on in the preamp, just by chance alone. When he switched to SE operation, that too would require shutting down the phono stage, and it could easily be the case that the premp does not oscillate at all in SE mode. If you have ever tried to chase down and cure an oscillation in a piece of audio gear, as I have done, you would know what a royal pain in the arse it can be. Took me over a year with an amplifier, and that was with help.

this is possible, but the mat suggests that it 

@fsonicsmith1 Wow

@mitchellcp  I think this problem is super interesting and part of what makes the hobby so fun (I think we're all gluttons for punishment).  Thanks for posting this, I've enjoyed learning from the other folks who are posting ideas. I am not sure if it has been asked and I couldn't see in the video, but does the woofer movement happen on both speakers and in phase with one another at the same time (both channels)?

Just to be clear, I’m not changing anything else until I have time and another excuse to play with wires, which will probably be tomorrow.

My primary reason for posting this was to see if anyone else had seen this and perhaps knew a solution. Google search yielded no results for this specific problem so I thought, why not? I can run it single ended with no trouble until I have time to dig back in.

@jpaulfreeland74 Great question and the answer is yes, it’s both and in phase.

fsonic, I don’t know what I said to make you so angry, but you DID write, ..."or degauss the current mat, or put a blocking capacitor somewhere." And this is what led me to believe that you were supposing that a capacitor can block a magnetic field. Even Sherlock Holmes could testify to that fact.

Mitchell, I apologize if you felt that I was discounting the thoroughness of your analysis. I was not, although your report as it is does suggest a few other experiments that could be done to investigate the matter further, rather than for the rest of us to just keep on guessing. The first of those would be to re-install the XLR connectors and determine whether you can reproduce the original phenomenon. But I also understand what a pain it is to change the connectors on your ICs, and if you don’t want to be bothered, that’s fine.

My point was and STILL is that it could be that some piece of gear in your signal chain (originally I mentioned the preamplifier, but it could also be the amplifier) is induced to oscillate under certain conditions. And this may have nothing whatever to do with the platter mat plus or minus an LP on top of it. (Hence, I used the term "red herring" in reference to the bit about the effect of the platter mat/LP) Oscillation can be very capricious, intermittent, and nearly impossible to reproduce when you want to investigate its cause. Turning a unit off will stop its oscillation, and when you apply power again, the unit may work fine under the exact same input and output loads. Like I mentioned, I have had a personal experience with an unstable amplifier that vexed very competent repair persons and then vexed me for another year when I took on the job of fixing it because no one else wanted to touch it. This amplifier oscillated when fed by a certain CDP but not when fed by another CDP, for example. On other occasions, the amplifier worked fine for months before it would go into oscillation solely due to music input. From a pragmatic point of view, if you are happy with SE operation, and if your particular problem never recurs, you really never have to know what was going on. Just enjoy the music.

@lewm 

lewm

11,075 posts

02-16-2023 at 09:46pm 

fsonic, I don’t know what I said to make you so angry, but you DID write, ..."or degauss the current mat, or put a blocking capacitor somewhere." And this is what led me to believe that you were supposing that a capacitor can block a magnetic field. Even Sherlock Holmes could testify to that fact.

You have me confused with someone else. I did not write that. 

@lewm you may be correct about the oscillating- not enough information right now. I’m re-wiring the tone this weekend with Audionote Silver and silver clips- I’ll have everything apart anyway so I might as well try again. 

fsonic, Mea culpa. A thousand apologies.  It was Holmz who wrote the sentence I quoted (and responded to), not you.

@lewm 

No problem. You are one of my favorite contributors on this Board so I'm glad to have that cleared up.

It is super interesting.
Do you access to a compass like hikers use?
I think even an iPhone with its magnetometer built in might work as a way to see if the mat is somehow magnetised.

Sure, it is possible, that it is somehow related to wiring… but I doubt it.

When I had a 50 Hz hum it was also from a magnetic field, and the coils in a MM or MC cart are effectively a magnetometer.

If it is only doing the pumping when the mat is on, then I would think that removing the mat would be a possible strategy to use to ameliorate the pumping.

Ok I tried the compass- nothin’

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. 

Not everyone is focused on magnetism. Have you read any of my posts? I’ve just grown weary of contradicting Holmz, who IS focused on magnetism. I let his last fantasy stand as is, because I did not want to appear to be picking on him.

Like I have said three or four times, my best guess is that the system is oscillating at a very low frequency when the preamplifier is hooked to the cartridge output in balanced mode. When the OP switched to single ended mode, the problem went away. The bit about the platter mat and LP is a red herring, as per my earlier definition. The fact that it seemed to make a difference can possibly be due to the fact that when you power down an oscillating electronic device (in this case, the preamplifier or the amplifier would be oscillating due to input from the TT), the oscillation of course ceases. When you then restart or power up the same electronic device, even with the same input and output loading, the isolation may or may not reappear. In order to remove the platter mat and LP, in this instance, the OP had to shut down power to the TT and then power it up again in order to demonstrate the "no platter mat, no LP" condition. So lets say the cartridge is picking up something from the TT motor that intermittently causes either the preamp or the amplifier to oscillate but only in balanced mode. The intermittent nature of an oscillation is what confounds the investigation of its cause, let alone trying to fix the problem. And beyond that, we really do not have enough data to speculate further. Maybe the OP will eventually come forward with some additional information, but I don’t blame him if he does not want to be bothered and is perfectly happy to operate in SE mode.

Magnetism, shmagnetism.

In the post above, the word "isolation" which appears in line 9 of the second paragraph, should be changed to "oscillation".  I thought I fixed that within the time limit for editing, but apparently not.

I wonder what would happen if you rub a dryer sheet over the rubber mat?

I think it would smell very fresh!

Kidding I’ll try that next go ‘round

I mentioned that I would be re-wiring my tone arm this weekend and I have completed that. I'm going to start a separate thread about the why of the rewire and it's results. For the purposes of this thread, I'm enjoying the improved sound so much there may a hold on converting back to balanced mode.

 

Not everyone is focused on magnetism. Have you read any of my posts? I’ve just grown weary of contradicting Holmz, who IS focused on magnetism. I let his last fantasy stand as is, because I did not want to appear to be picking on him.

Like I have said three or four times, my best guess is that the system is oscillating at a very low frequency when the preamplifier is hooked to the cartridge output in balanced mode. When the OP switched to single ended mode, the problem went away. The bit about the platter mat and LP is a red herring, as per my earlier definition. The fact that it seemed to make a difference can possibly be due to the fact that when you power down an oscillating electronic device (in this case, the preamplifier or the amplifier would be oscillating due to input from the TT), the oscillation of course ceases. When you then restart or power up the same electronic device, even with the same input and output loading, the isolation may or may not reappear. In order to remove the platter mat and LP, in this instance, the OP had to shut down power to the TT and then power it up again in order to demonstrate the "no platter mat, no LP" condition. So lets say the cartridge is picking up something from the TT motor that intermittently causes either the preamp or the amplifier to oscillate but only in balanced mode. The intermittent nature of an oscillation is what confounds the investigation of its cause, let alone trying to fix the problem. And beyond that, we really do not have enough data to speculate further. Maybe the OP will eventually come forward with some additional information, but I don’t blame him if he does not want to be bothered and is perfectly happy to operate in SE mode.

Magnetism, shmagnetism.

Yeah @lewm I am guilty as charged.
Your posts are usually pretty thoughtful, so I would probably be OK with being picked on.

WRT the air currents and wind, just blowing on the stylus would be more that it would see from currents, and if that does not move the stylus then to get LF movement would be pretty hard.

And resonance of the stylus/cantilever should be much higher freq, that the <1 Hz.

So I am thinking the causal mechanism is doubtful to be mechanical… which leaves electrical and magnetic as two forces.

@mitchellcp I have lost that ball a bit, but we may want to see of it pumps moving the TT patter by hand, or as the thing is spinning down right after the motor stops getting power.

If it does it with only the motor being on, or regardless of whether the motor is powered, then that would be “more clues.”

@lewm I am starting to come around to your hypothesis, as it seems like it what is known as motorboating.

It looked like it was sync’ed to the platter position, and platter speed.
I am wondering if the pumping is faster at 45RPM than at 33-1/3?

It pumps to the rpm of the platter. 33 at 33, 45 at 45, and slowly if I spin it by hand.

Bear in mind, that isn't happening now because I'm in single end mode.

Yeah, @mitchellcp you said this in an earlier post - "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."

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

Also, when you tried 33 and 45 did you turn anything off in between? I ask because @lewm talked about turning on and off equipment can yield different results with the oscillation idea.

Not sure this below is representative, but it is interesting:

I managed to reproduce woofer pumping, with my old Dual 701/V15III (direct drive) unplugged from wall power, the platter on or off, and just having the stylus near the motor housing and spinning the housing or platter by hand. More pronounced with the platter off. I can go real slow and get real slow woofer pumping, or faster and get fast woofer pumping. Move the stylus further away and no pumping. I had to turn the gain almost to full to see anything though; increasing the gain on the phono stage increased the extension of the pumping (makes sense).

I also reproduced this, but it was much more mild woofer movement, with my old Technics SL-D20 (also direct drive), again unplugged from wall power and just spinning the platter by hand.

@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.