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Woofer pumping WHY??

Hello All, I have an older REL B2 series. I love this sub. I recently received a new Project Xtension 10 with Clear Audio Maestro Ebony v2. After a couple days I noticed bad woofer pumping on several records I like to listen too. When I brought it up to Needle Doctor they told me it was my records and said it worked fine in there store. Now my REL is blown! I am so upset at myself for not taking this matter more seriously. Now I am purchasing a KAB rumble filter because I am not going through this again. Is this a cartridge mismatch?? Because on my REGA with Dynavector 10X5 It did not do this woofer pumping nearly as bad. AND I do remember putting a DENON DL103 on my RB301 and this same woofer crazy action occurred!! Immediately took it off that arm. I just spent $4100 for this Xtension10/CA Maestro and now I am scratching my head. Hmmmm.
128x128mattmiller
jperry
2,462 posts
 
"07-21-15: Dougdeacon
When I play any vinyl it goes 4 very quick beats then nothing then 4 very quick beats and so on... it even speeds up when I play 45's
Good observations, which lead one to suspect an irregularity in the new TT's drive or bearing system."

I have never had an issue like this, but amplifying on Doug's suggestion I would put a piece of painter's tape on the side of the platter and see if the pumping correlates with the tape location.

If that happens, and your Rega does not have this issue, you should call your retailer and have a more detailed discussion. It could be that you have a defective turntable and they should work diligently to help you resolve this issue, regardless of whether it is system based or a defective turntable.
dougdeacon
3,338 posts
 
Good followup suggestion from Jperry. I would try his simple diagnostic and my suggestions before schlepping a hunk of granite, which seems unlikely to alter the behavior last described.

Do whatever you like of course.
mattmiller's avatar
mattmiller OP
1,502 posts
 
I don't have much faith in the "higher mass shelf theory" but Its easy for me to test that one. I really think the new Project Xtension 10 is not the problem. All the table has done is push a lot more music through the system than before. Also, made it a lot more sensitive to play vinyl. I have 2 cheap phono preamps and I think one is even going bad. So, there is a lot going on that's not good right now. This is very interesting to me also though. I am sure there is a resolution coming soon.
rodman99999
6,206 posts
 
From your description of the woofer motion(four large excursions/stops/four large excursions/stops/etc); neither acoustic feedback or tonearm/cartridge resonance are your problem. As Mr J stated; you'll find it's mechanical(belt/bearing/platter). If it's under warranty, take it back.
sbrownnw
710 posts
 
I had woofer pulsing with my pro-ject xpression III. Went to a regs rp6 and no more woofer problems.
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