Uggh, vinyl!
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
Audiotomb it has happened on all carts on both TT’s. Grado Sonata 3 (new) Nagaoka MP200 (<200 hrs) Nagaoka MP500 (<300 hrs) Soundsmith Carmen II (<300 hrs) they have all been aligned Using the AS Smartactor which takes error out unless you can’t read and follow basic direction. Also, both TT’s causre the pumping time be exactly the sameAnd at the same volume, even though one is DD the other belt driven, one light aluminum platter with stock rubber mat the other a 25 lbs aluminum platter with deer hide mat. I’ve sat them in the floor (concrete) to eliminate vibration as an issue, no change there either. In fact only thing the two TT’s have in common is the alignment. Could this be a cause? |
From what is described here was very common long ago. Noticed this in high school. Now to a lesser degree. Warped Vinyl. We had Sub Sonic or Rumble filters on our electronics to almost deal with it. Back in the day we treated records like cd's. Worst! A $12.95 Astatic cartridge on a Magnavox phonograph could make my woofers dance with a warped record. Now my delicate handling and care of my vinyl borderlines an illness. When that stylus cantilever assemble designed to pickup microns of movement deflects .5mm up and down, your woofer is going to move. |
I have a VPI Classic 1 with Lyra kleos and Zephyr when Kleos is being retipped and never had my woofers and subs pumping. Always had it set on concrete slabs, but I doubt that would make much difference, also use an outer ring but go without it at times and regardless of warp, I experience no woofer pumping. Something is obviously wrong with your setup and I hope you figure it out. |
Yes the VPI pivot setup doesn’t involve a bearing - doh! Watch the cartridges on the record Is the cartridge moving up and down but most of the movement is in the cantilever? (The cantilever angle should be static) If that is the case - the suspension on your cartridge has weakened and would result in woofer pumping. You said you had swapped things in and out. Is one Cartridge or turntable more prone to woofer pumping? Both cartridges could easily be having these Suspension issues |
Tom, Thanks for your input, while the pioneer is a traditional gimbal arm the VPI is pivot. As you probably know there are no bearings per se, to be sure I checked the pivot point and the cup, both are free of debris or burring. I also have the second pivot point for the VPI and I even disconnected it to be sure, but the pumping happened in both cases with and without the second pivot point to the same degree. |
Not sure if this is your issue but In 2010 I have a very significant woofer pumping issue with vinyl That’s when I had a triplanar arm and ZYX Universe cartridge We looked at isolation, the room, Speaker porting, suspension, etc etc like you are doing. Like your situation it was worse on the outside portion of the record and exasperated on records with subtle warps a lot of great insight from those posting here and our local guru here in New Orleans Richard Gray and Thom Mackris of Galibier converged on a solution. Major thanks to both. Finally resolved what was wrong the feather test - moving a feather lightly against the cartridge on the outer side parallel to the record should move the head shell and progress the record forward if the cartridge doesn’t respond to the feather’s light touch and move inward then The tonearm bearing isn’t moving properly The tonearm bearing wasn’t moving suficiently so the cantilever was moving up and down some instead of the cartridge moving in mass. It would follow the groove forward but not have enough sensitivity to track things vertically correctly in harmony with the cartridge. That was what was causing all the pumping It also isn’t kind to your deliccate cantilever suspension. Most likely the bearing was restricted by dust in the equation. I had the arm sent back and the bearing replaced by Triplanar and all was well Since then I move up to a Durand tonearm. I know you mentioned this was occurring with two turntables but each could be suffering from the same bearing issue to different degrees. I wouldn’t rule the tonearm bearing out. Particularly if you hadn’t played them in a while, there were similar dusting habits or if they are located in the same environment. It is certainly worth a test. Tom |
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Well other than a clamp that works wonders, I’m not sure what is left for me to try. Here is a list of things most things I’ve done: different cartsHead shell weightsAdjusted tracking force different count wts different antiskate checked leads different mats different TT’s - in various locations different phono pre different pre Amps checked different inputs on preamp different amps moving TT to concrete floor Different cables lifted motor off table so only belt spun platter not sure what to check next. I would have thought that two different turntables without we skipped two different results but it doesn’t |
stereo5 It is not the turntable. I tried my VPI with 3 different clamps and none made any difference. I still use the KAB with my Technics SL1200G and even though the noise was less it wouldn't go away until I used the KAB ...If it's not the turntable, or the match between cartridge and pickup arm, then it's the set-up. Rumble filters are really a Band-Aid. They work, but treat the symptom, not the root cause. |
Wrong on all of it. You tried three different clamps. If none of them are designed like I said you could try a hundred more and it won’t prove a thing- other than that a lot of record clamps are of poor design. Which is why I made my own. There are some good ones out there. I described exactly how they should look and work. Get one and use it. Problem solved. |
@last_lemming, It is not the turntable. I tried my VPI with 3 different clamps and none made any difference. I still use the KAB with my Technics SL1200G and even though the noise was less it wouldn't go away until I used the KAB. I used every type of isolation platform known to man on the 2 turntables I had, the VPI Prime and the Technics SL1200G, no difference. I believe the stylus is picking up the sound from the speakers and re-amplifiing it. The KAB filter is around $180-190.00 and it uses all audiophile approved high end parts inside. Using it I am very much enjoying my vinyl collection again with no loss of sound quality. To add one more thing, my Audible Illusions Modulus 3B had a subsonic/rumble filter and it did nothing, hence the KAB. |
I can’t discount your thoughts about the clamp, but how would this affect the outer edge of the record where there is no clamp. I’m right about everything. All you have to do is read what I write. last_lemming: how would this affect the outer edge of the record where there is no clamp. millercarbon: My record clamp is dished out inside, so as its clamped down it presses the record down onto the platter from the outside edge in. Got it? From the outside edge in. last_lemming: I use a heavy record weight - which I know you say is no good - but it firmly holds the record onto the deer hide mat.Where did I say deer hide mat? millercarbon: as its clamped down it presses the record down onto the platterSee? Platter. Not mat. Platter. Ditch the deer hide mat. last_lemming: I’ve also tried several matts to no avail. Yes, because that is part of the problem. Ditch ALL mats. |
I meant ALL my TT’s do it with ALL carts - exactly the same. What are the chances of duplicating the issue between to different TT’s and different carts. Also the carts compliance works with the arms, so there is no mismatch to be concerned here. What, I’m saying it’s VERY unlikely linked to an issue with the TT itself, but has to do with the subsonics coming off the record that both TT’s are picking up. |
"...it is not the turntable or cartridges..." "...To be certain it was limited to vinyl playback..." A bit of discrepancy in your conclusion but the cause is typically the ultra low frequency rumble from the turntable/cartridge combination. Check the Analog section or do a search. Lots of discussions and recommendations on this very subject. |
I moved both TT’s - all over the place. Not change at all and that’s spiked through to the concrete floor. Miller, I can’t discount your thoughts about the clamp, but how would this affect the outer edge of the record where there is no clamp. I use a heavy record weight - which I know you say is no good - but it firmly holds the record onto the deer hide mat. I’ve also tried several matts to no avail. You’re definitely right about one thing, it’s not the amp, I just pulled out my old CJ MF2100, and I get it there too. So there goes that theory. |
Lord. Of course its the turntable. Specifically, its the way the record is clamped to the platter. ALL records, if you just plop them down, are going to produce some degree of the very low frequency energy that you see as woofer pumping. When I play records, any volume, there is plenty of bass and no woofer pumping. Without filters. Horrible idea! Look at my system. Please. Took the time to post the pics for a reason: so everyone can learn. Study, observe, and learn. Please. https://systems.audiogon.com/systems/8367 Look close at the platter. Notice the black ring around the spindle? Looks like a washer. Its not. Its carbon fiber. Its hard to take a picture from an angle that shows every detail clearly so you have to really study it. Which you should do! Totally worth the time. See how thick the washer is? A record placed on this is held just very slightly higher than the surface of the platter. If played like this, or if any record was played on this same table without the washer, just sitting on the platter, there would be all kinds of woofer pumping. Because at the scale of amplification we use even near invisible amounts of vertical motion at the record translate into a totally obvious pumping at the woofers. The fact you mention being able to see the tone arm move AT ALL tells me you’re not even close to doing it right. So the next step after placing the record on the washer that holds it too high is to clamp it down. My record clamp is dished out inside, so as its clamped down it presses the record down onto the platter from the outside edge in. Fully clamped the record is absolutely flat on the platter. Its clamped so flat that when the clamp is released its like its been suctioned down onto the platter, which you can tell because when the clamp is released the records stay down for a second until air comes in and it pops up. This is what you want. Its not your amp. Forget about that. Waste of time. Don’t move your table. Its embarrassing how far off track some of these ideas are. Look for a good clamping system. Clamp. Not weight. Clamp. |
I have the KAB Rumble Filter and it is amazing. No sound degradation whatsoever. I have a/b back and forth probably close to 100 times in the 7 years I have owned it and once the levels have been carefully matched which I can do on my Mac C2500 preamp, there is zero difference. The 7 or 8 friends that have heard it concur with me. In my system due to the location of the Turntable in conjunction with the speakers, It is one of 2 solutions. The other is to stop playing vinyl. |
