@ last_lemming, Turn off the oven/range breaker at the panel. Then play the audio rig. To see if you still have woofer pumping. Mike :-)
Woofer pumping possibly due to tube amp when playing vinyl
I am moving this issue to this forum because of what I discovered this weekend.
I’ve been trying to figure out why I have woofer pumping when I play vinyl, and for the last two weeks I’ve been messing with my vinyl rig trying to figure out what is causing the issue. The woofer pumping seems to be more prevalent with the vertical up-and-down movements of the tonearm regardless of which turntable is being played. It appears it happens more at the outer edge of the record then the inner grooves. I assume this is because record is more warped at the outer edges. The woofer pumping happens even in quite passages, so it’s not noise induced vibration affecting the turntable.
I have used two different turntables to try to figure this out, one is a pioneer PL 530, and the other is a VPI prime. both with different carts. Also, I have verified that all the carts being used on these turntables work well together with their respective arms.
However, it is not the turntable or cartridges.
Things I can say for certain, it is not the turntable because I switched turntables with different cartridges to confirm this, and I still get the woofer pumping. It is not a phono preamp because I’ve switched several phono preamp‘s, solid state and tube, and I still get the woofer pumping. It appears it is the tube amp that may be at cause. It’s the only component left of the chain.
I have a Audio Research Classic 60 amp. I got the amp used but it came with a new set of power tubes I don’t recall if I changed the four smaller driver tubes, I also change the four large capacitors to new capacitors and biased the amp.
The interesting thing is, with the TT’s I tried, it is the right channel that pumps more than the left channel, regardless of the variety of different cartridges tried, all aligned with AS Smartractor.
To be certain it was limited to vinyl playback, I plugged in a CD player and I do not get the woofer pumping at all. So I have a couple theories (1) the TT is just transferring subsonic frequencies from the records, ALL records I play do this. Please remember, this is from the two different turntables being used, one a VPI prime belt driven, and the other a pioneer PL 510 Direct DrIve, or (2) there’s some weird thing going on at the amp that I cannot explain.
My question is, if there is something going on with the amp could it be a tube issue, or capacitor issue, or a biasing issue. If so what is the most likely culprit. Or I guess something else altogether.
In the end I’m rather tired of chasing this ghost, and I would rather not use a subsonic filter if possible. If I do have to use a subsonic filter I want the most transparent one if such a thing exists. I’ve heard mixed results about the KAB unit.
I’ve been trying to figure out why I have woofer pumping when I play vinyl, and for the last two weeks I’ve been messing with my vinyl rig trying to figure out what is causing the issue. The woofer pumping seems to be more prevalent with the vertical up-and-down movements of the tonearm regardless of which turntable is being played. It appears it happens more at the outer edge of the record then the inner grooves. I assume this is because record is more warped at the outer edges. The woofer pumping happens even in quite passages, so it’s not noise induced vibration affecting the turntable.
I have used two different turntables to try to figure this out, one is a pioneer PL 530, and the other is a VPI prime. both with different carts. Also, I have verified that all the carts being used on these turntables work well together with their respective arms.
However, it is not the turntable or cartridges.
Things I can say for certain, it is not the turntable because I switched turntables with different cartridges to confirm this, and I still get the woofer pumping. It is not a phono preamp because I’ve switched several phono preamp‘s, solid state and tube, and I still get the woofer pumping. It appears it is the tube amp that may be at cause. It’s the only component left of the chain.
I have a Audio Research Classic 60 amp. I got the amp used but it came with a new set of power tubes I don’t recall if I changed the four smaller driver tubes, I also change the four large capacitors to new capacitors and biased the amp.
The interesting thing is, with the TT’s I tried, it is the right channel that pumps more than the left channel, regardless of the variety of different cartridges tried, all aligned with AS Smartractor.
To be certain it was limited to vinyl playback, I plugged in a CD player and I do not get the woofer pumping at all. So I have a couple theories (1) the TT is just transferring subsonic frequencies from the records, ALL records I play do this. Please remember, this is from the two different turntables being used, one a VPI prime belt driven, and the other a pioneer PL 510 Direct DrIve, or (2) there’s some weird thing going on at the amp that I cannot explain.
My question is, if there is something going on with the amp could it be a tube issue, or capacitor issue, or a biasing issue. If so what is the most likely culprit. Or I guess something else altogether.
In the end I’m rather tired of chasing this ghost, and I would rather not use a subsonic filter if possible. If I do have to use a subsonic filter I want the most transparent one if such a thing exists. I’ve heard mixed results about the KAB unit.
127 responses Add your response
I understand that you’ve tried two amps, but problem is an incompatibility between your chosen speakers and your chosen amps. Review the specifications of your components and make sure that the numbers work in theory. If you value your amps more, then purchase a more compatible speaker. If you value your speakers more, then purchase a more compatible amplifier. Either way, problem solved. |
definitely don’t agree with the “need a better table than the ones listed” comment. All 3 of these tables have been in another system with No issues. Today I brought my other system in the same room as the offending system. Mind you the other system with same record doesn’t pump the woofers. But in this room, guess what, pumps the woofers. And, oh, when I bring the original offending TT and cart to the room with no issues, guess what, NO pumping. And don’t forget. I get pumping in the quiet passages in all things I’ve tried. So now a total of 3 tone arms, 5 carts, 3 surfaces to place TT on, 3 phono preamps, 3 amps, 3 preamps, 3 different outlets through out the house, 3 sets of speakers, 2 different alignment styles, and untold number of combinations of the above not to mention all manner of alignment adjustment have brought zero differences in the amount of woofer excursion, accept for when the mono switch was thrown, which did lower it about 30% (best guess). Here is what I do know. 1. It happens with any turntable in this room regardless of all things done above to alleviate it. 2. CDs don’t cause any pumping. 3. The pumping isn’t caused by speakers resonating the TT, since it happens on quiet passages and at lower volume levels. 4. regardless of placement In room or surface: concrete, rack or carpet I still get pumping. 5. None of equipment, including any of three TT’s, amp pump in the other room. So what does this mean? Well, there must be some type of EMI or similar coming from something in the walls or in this area of the house interfering with the TT set up. Though the only thing I can think of if the oven/range on the opposite side of the wall. I might be at the KAB point, unless I can figure out what’s the root cause. |
cause of the pumping woofer is rumble and it's inherited to vinyl playback. there is inevitable friction between tip of the stylus and groove walls while playing. additionally if your stylus is worn out it can reach the bottom of the groove and cause more rumble. on the other hand turntable, tonearm and cartridge quality plays a major role on rumble but unfortunately you can not totally eliminate it. you can only lower it to an acceptable level. people who are saying that there is absolutely no rumble on their turntable are either not aware of the existence of an embedded rumble filter on their phono preamp which can not be turned off or don't have a speaker that can go below 40Hz. in order to lower rumble to an acceptable level you need a much better turntable and tonearm than the ones you mentioned. |
Yes the KAB is an option, but I want it to be my very last, but only after every other variable has been looked at. While I know some say it’s transparent, others have said otherwise. To be clear the rack has not been constant. Anything but. The TT’s have been on concrete, carpet , rack, on and off maple block, with and without bear claws, different locations in the room, with and without record clamps, and all this tried with three different turntables, two amps, two preamps, three phono amps, different speaker cables, various IC’s, and even different power cables and outlets. It’s something with the room. I can’t figure what, but I’ve basically changed all components out, so what’s left is the room, and it’s not room interactions, because I hooked up a speaker with a very long speaker cable and ran the speaker outside the room the equipmentIs in, and it still pumped. It’s driving me nuts! I don’t want to add a KAB to fix a problem that is not caused by the equipment. |
Despite swapping out turntable/cart/phono stage, your constant factors here are: your rack/mounting/floor under the turntable, its location (relative to the speakers too), and your (lack of) clamping over the whole record surface. You could leave everything as-is and attack this with the KAB rumble filter, but other than that these are the variables to play with. |
No idea if this will help or if you have eliminated these potential causes, but I had a similar issue with my Pioneer and in my case there were multiple things happening. The one cause was the turntable being too close to the magnetic fields of my open baffle subs. Moving the turntable helped. The other cause (which is less likely in your case) was that the potentiometer (dial) used to adjust the speed had dirty contact issues which caused the direct drive to "flutter" for the lack of a better word. You could see the speed changes on the strobe. The magnetic fluctuations as it kept trying to adjust the speed were picked up by my MC cartridge making the bass pump. A dose of de-oxit sorted that out. In either case and EMF meter could help determine if a magnetic field throughout your home is the source. |
And now I tried it with a third TT and cart. A Technics 1200 GR with an AT33sa (MC cart) and the pumping still goes on. And this time the TT was carpet, so no way vibration traveling through the walls or floor. Also, this same turntable and phono pre does NOT cause pumping on my other system. Again, not the TT. I also switched in my Parasound JC3+ Phono pre on this system and the pumping still continues. So not the phono pre. Also please remember I get the pumping on the lead in track with NO music, so vibration through sound is not the culprit either. In fact after 3 turntables with different carts and positions and surfaces within the room it’s defiantly NOT any of the 3 turntables. For kicks I plugged in another speaker on the right channel, unplugged the left channel, and moved The speaker all around the room to see if reverberation was the culprit, but nothing changed, The woofer consistently pumped. So it’s not the speakers or the sound coming from the speakers causing feedback and pumping. I also pugged the whole system into various other electrical outlets In the house just to check if it’s the electricity, that did nothing to help. The only thing that appears to be constant is the pumping is worse at the beginning of the record vs the middle. |
Last_lemming I had the same problem a few years ago. I had the same turntable for years and never had a woofer problem. I then moved and in my new room the woofers started pumping. I remember this problem back in the 70’s and 80’s and thought turntables built today couldn’t possibly have this problem. It’s the room. Some vibration is getting into the turntable to cause the woofer pumping. That’s why, even though you placed the turntable on the concrete floor the turntable was still causing woofer pumping. A concrete floor still gets vibrations from the earth. I tried the same thing. I solved the problem with the Symposium Acoustics Segue ISO turntable platform. They can be bought through Acoustic Sounds. There are two types of these platforms one for lower weight turntables ( I think up to 40lbs) and one for heavier weight turntables ( up to 80 lbs). This will solve your problem. |
One thing I do know is that a deer hide mat is not an issue for the problem. I use one in combination with a center weight and extremely satisfied with results. I was wondering if the VTA of the cartridge was evaluated or tweaked, I do know a rake greater than 93% can cause audible issues. You have to use a digital microscope to view the position of tip/cantilever to verify. The manufacturer doesn't always build the stylus to the specifications they advertise. |
All my carts I have tried fall within the correct EM range.This gets tricky- even cartridges suggested by the manufacturer of the arm may not be ideal. This can be because the actual performance of the cartridge (in this case, the compliance value) might actually be considerably different than the spec on paper, the latter of which the manufacturer may have used to make a recommendation without actually having used it. That is why trying a cartridge with a lower compliance value is a good test of this hypothesis. |
I got the Kab filter yesterday and ran it through the Loop in/out on my amp. Woofers stopped pumping and bass cleaned up from sub. I haven't had a chance to fully demo it but I'm definitely keeping it. You can enjoy your vinyl collection for $180 while you spend the next few months and who knows how much money finding a better solution, and then just sell the Kab filter on e-bay when you do. |
I can also tell you the clamp isn’t the solution. I’ve got the VPI clamp that is dished on the underside and comes with a washer, but unless your clamp goes all the way to the edge of the lead in grooves, It ain’t gonna flatten those slight rises (Bumps) in some records right at the edge I don’t care if you tighten it down with the force of Superman, it won’t flatten those types. A perimeter ring would help but they are pricey and kinda look like a PIA to use. But maybe that’s better than using a subsonic filter. If I thought there wouldn’t be a degradation in sound I’d use one. But anything that I’ve ever added to the chain that claims no degradation always does. |
@ last_lemming, I concur, with mijostyn. It is what i said and strereo5 said in the first two posts. (Subsonic filter.) My turntable has a air platter it sucks the record flat to the platter like a pancake no warps. And i have a (clamp.) With out the subsonic filter, i have the same problem as you do. That is why i said move the table to a different room. When i moved my table to a different room no woofer pumping. I put the table back in my audio room woofer pumping is back. I put the subsonic filter in woofer pumping gone.! I do not use subwoofers. (My subsonic filter is analog.) That is my experience. Hope that helps. Mike :-) |
Should have mentioned that there is a resonance calculator on the Vinyl Engine site that can be used to estimate resonance based on the effective mass of the tonearm, compliance of the cartridge and the weight of the cartridge/hardware. No substitute for an actual measurement but it will at least tell you if you should be in the ballpark. |
mijostyn Many amps roll off below 20 Hz so you won’t see woofers pumping.Not good ones. Your system is doing exactly what it is supposed to do. Moving the turntable won’t change a thing. Anybody who uses subwoofers aggressively and plays vinyl will need a subsonic filter ...Oh no, that’s mistaken. Completely. I don’t use a subwoofer, but I do use a full-range speaker system that is essentially flat in-room to below 20 hZ. It’s awesome. My phono stage, line stage, and bass amplifier (this is a bi-amped system) are all rated to far below 20 hZ. The system can produce bass that you can’t hear but can only feel. No rumble filter. No woofer pumping. Ever. The best subsonic filters are digital.I think the best subsonic filter is no subsonic filter. |
I am assuming this problem only shows up when the stylus is on the LP surface. I would see if you can try out a cartridge that is a bit less compliant and see if that sorts things out. Woofer pumping is a common complaint if the cantilever has too much compliance for the mass of the arm and cartridge together (along with the position of the counterweight, this contributes to a value known as 'effective mass'). The effective mass, along with the compliance of the cantilever, results in a another value known as 'mechanical resonance'. Ideally this should be between 7-12Hz. If below that, woofer pumping can be an issue! You were asking earlier what the chances could be that two turntables have the same problem and the answer is 'quite high' if no attention was paid to this issue. So its worth it to borrow a cartridge that has lower compliance to see if it gets sorted out. |
Many amps roll off below 20 Hz so you won't see woofers pumping. Your system is doing exactly what it is supposed to do. Moving the turntable won't change a thing. Anybody who uses subwoofers aggressively and plays vinyl will need a subsonic filter. The problem with many rumble filters is that they start rolling off between 30 and 40 Hz so your audible bass is affected. Woofer pumping is a big problem. It wastes power and forces your drivers into non linear operation increasing distortion. The best subsonic filters are digital. My filter starts at 18 Hz and is 60 dB down by 1 Hz. It is totally transparent. If you switch it in and out playing a digital source you can not tell the difference. If you switch it out playing vinyl?? I have 4 12" subwoofers each one driven by 2000 class AB watts, damping factor 500. With some records the drivers will bang against their bump stops! This is just one advantage in having a digital front end aside from bass management, room control and equalizer functions. If you have subwoofers, play vinyl, and have amps that go down to DC you positively, absolutely need a proper subsonic filter. |
The operable range of the speaker is usually described as the range in which it will reproduce sound, which is why a +/- dB specification is the norm. That doesn't necessarily describe the range of frequencies that the speaker can physically respond to - you can put a 1Hz signal into a speaker and the cone might move but you wouldn't hear it. In terms of the proximity of an appliance or source of the subsonic signal, that can travel a long way, especially in a solid substrate. Earthquakes, trains and sonar are good examples. Given all of the tests you've performed so far, swapping channels and even equipment, it's hard come up with any source of the movement directly related to the electronics (I'm including the cartridge here). Does your preamp have a mono switch/setting? Switching to mono should cancel the vertical component of the cartridge output You may have tried that and I missed it. Finally, is there any chance that the speakers themselves are contributing to the problem, perhaps through differences in the crossovers or the drivers themselves? Very unlikely, but something that might be relatively easy to check. Have you tried swapping the speakers left/right? Physically isolating or moving the speakers? If the pumping is altered by any of these changes it might point to a cause. |
Larryrs, I have considered this but the nearest appliance is a gas range opposite Side of the wall. If there is a phone app I’ll certainly give it a try. Got nothing to lose. One thing I don’t understand is the speakers go down to 32hz, but sub-Sonics can be far lower, so how do the speakers reproduce below there operable range with such amplitude as to move the woofer in and out 1/4” or more, when my strongest bass note I can get when turned up only moves the woofer 1/16”. |
@ last_lemming, have you measured the vibration at the turntable platter directly? I have an app on my phone that will measure vibration on a surface in the X-, Y-, and Z-axes. It might be instructive to get some sense of the magnitude of any disturbances that might be causing the woofer pumping. It can also be useful to determine if any vibrations might be cyclical in nature. This could be the case if an appliance (e.g., a refrigerator, air conditioner, heating plant) is the source of the problem. Have you measured any vibration on the walls or the floor of the room, either with your hand or using some sort of instrument? Seems like you've exhausted pretty much all of the more system-specific possibilities so maybe it's worth looking for another environmental cause. |
This issue does not have anything to do with a tube amplifier. You need a better turntable and a subsonic/rumble filter. I am surprised you see it on a VPI however since it is usually a better turntable. The rumble usually (but not necessarily only) comes from the main bearing of the turntable and is at very low frequencies (8 - 20 Hz). You can sometimes hear it and more often actually see it (as you have in your woofer). It is the noise generated from the bearing shaft & the sleeve grinding against each other. No matter how excellent and/or mirror polished the main bearing may be, at the end of the day, they are still two separate pieces of material grinding against each other. You should see it under an electron microscope and you will understand :-) Typically good turntables have a rumble figure of less than about -75 db or so (quiet). Excellent ones reach down to -82db ish (very quiet). You can reduce it but never eliminate it completely. It becomes pretty audible and a nuisance at around -70db or higher (give or take a few dbs, not an exact science). Limitations of analog playback :-) |
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Thanks for all the input, here are some of the responses to some of the questions: The platter is dead level I’ve checked it out digitally and with a old fashion bubble level I’m pretty sure it’s not the phono preamp, I tried a Dynavector mkiii phono pre and an an Audio Research PH3se phono pre, it does it on both. I have a Parasound JC3+ in another system, so I might try hooking that up as well to see if it happens. Audiorusty i have those pads too, and tried them. No change. |
I had a woofer pumping issue when playing vinyl a couple of years ago. The first thing I did was make sure the TT was as level as I could get it which helped a little bit. The other thing I did was place the TT on some anti-vibration pads like these https://www.amazon.com/PneumaticPlus-Anti-Vibration-Rubber-isolation/dp/B00HZS0CH6/ref=sxts_sxwds-bi...and the issue for me at least was eliminated. |
I use a TTW audio outer ring extreme V2, made in Canada. Extremely efficient and much less expensive than the VPI outer ring. That being said, once again, I don't believe that's your problem since I have never experienced the woofer pumping you describe before I got my outer ring even so I played some seriously warped vinyl. |
Millercarbon, your system must cost a fortune. I can't believe you are satisfied with listening to music in that kind of environment. I like to incorporate listening into a beautiful room such as a family room so when I have company they can enjoy the music as well. However, I am sure your system must sound incredible. I noticed you have speaker wire stands. What do they do and can you really hear the difference. Looking at your system, there must be a lot of wealthy people in this group. However, it is nice to learn from those who have invested a lot of money into their systems to achieve near perfect sound. They must have near perfect ears to hear the difference or they have dialed in the sound that best maximizes their hearing. What might sound perfect to one person must not necessarily sound good to another. Nothing wrong with dialing in the sound best suited for your hearing because it is who is listening and who is investing this kind of money that matters. I often think about this realtor who sends me listings of homes being sold in my area over the past 3 years. He has sent me over 1,000 listings and I have yet to see one room with a pair of speakers standing. I cannot believe people have a $5,000 piece of furniture with a wide screen TV and are willing to listen to the TV speakers. I think 70% of the experience when watching to a movie is sound. I also can't believe they don't like music. Nothing nice than to have people over for cocktails and listen to music in the background. I think most people are allergic to music are simply think music is noise. |
@last_lemming Since a number of things have been tried on the 'table, I am starting to suspect the phono section might be playing a role. What kind is it? The fact that its a problem with the turntable and not the CD player rules out the line stage and amplifier entirely. So it is either the preamp or the turntable, and the chances of duplicating the issue between to different TT’s and different carts.-is actually a lot higher than you apparently suspect! BTW woofer pumping has nothing at all to do with whether circuitry is tube or solid state. I agree that ditching the deer hide platter pad is a good idea. A proper platter pad will damp ringing in the platter and also vibration in the LP itself; deer hide will help with neither. I would think that the deer hide will be really tricky to maintain a uniform thickness- that might actually be the problem right there. |
paulgardner-
@millercarbon Can I ask where you got a carbon fiber outer ring clamp? I need one!Everyone does! Took mine to CES one year, compared with a bunch of em, its a great clamp. DJ Casser must have been impressed, he copied it, and so his stolen from me copy is as far as I know the only one on the market. Mine being DIY and a one-off. Its made from some BDR Shelf material that was left over after making the Miller Carbon turntable. https://systems.audiogon.com/systems/8367 DJ died about a dozen years ago, his heirs seem to be keeping the company alive but its not like it was. Far as I know BDR is only sold through Music Direct. I would call and ask if they can make you a record clamp. It will cost a lot. It will be worth it. Only clamp I know better than mine. Better made, better sound. He stole the design but give the man credit, he also perfected it. If they can't do that the next best would be order one of the Round Things with the threads going all the way through. Make sure your spindle is threaded to use this. Otherwise you need a collet type clamp. Which let me know, it can still be done its just more work. But a Round Thing, you can see them in my System pics, they are round and almost the right size. A little small but still better than every other clamp on the market. Then either dish it out like I did, or get an O-ring the right size to go around the perimeter so it pushes the record down from the outside area of the label. Then put a washer, or a small O-ring, near the spindle. That is the key. To push the record down from the center to the outside edge of the label, so when its clamped down the outer edge of the record contacts the platter first. This works just amazingly well. I really don't know what's wrong with the people here. They're talking about anti-skate, and every single crazy thing a guy could possibly imagine that can have nothing to do with it, while stubbornly refusing to see the one thing that will. Ignore the herd. Get a clamp. You will see. |
