Inner groove "Rumble"


All of a sudden, I'm hearing a weird "rumbling" once the stylus reaches the last inch or so of a record. There has been no sudden "trauma" to my table or tonearm. The first 80 % of each LP side still sounds absolutely fine. Any thoughts as to what's happening here ?
adam18
Adam, Your dog will probably like it more if you sit with him inside in an air conditioned room and listen to music, rather than taking him on a hike. Just take him out once a day for a romp and a poop. Dogs don't need the exercise
05-29-13: Adam18

"But, as summer approaches.... a lot more time with golf, bike riding, hiking with my dog, and all kinds of outdoors stuff ..... and a lot less time sitting in my basement music room !"

Are you crazy??? LOL!
Hey Guys........
No ..... I have not lost interest in this forum. Sometimes "life gets in the way" and Audiogon takes a back seat to other things. The bearing seems fine, and I think I've narrowed it down to a cartridge problem. I'm going to try to borrow a similar Rega cartridge and mount it to see if that improves the situation. Thanks for all your help and thoughtful advice ! I really appreciate all the interest you guys have shown, and it certainly is a pleasure being part of this fine Audiogon community ! I will keep you all posted as things progress. But, as summer approaches.... a lot more time with golf, bike riding, hiking with my dog, and all kinds of outdoors stuff ..... and a lot less time sitting in my basement music room !
Dear Lewm: Well, that already posted by other persons and I think he needs all the possible " reasons "/speculations.

Regards and enjoy the music,
R.
Raul, How can you rule out the most obvious (to me) possibility that the platter bearing is worn or low on lubricant? He most lately said that the rumble is audible at all points across an LP. But he has lost interest, and so therefore have I.
Dear Adam18: Seems to me as a cartridge suspension or a tonearm bearing problem.

It's dificult to say for sure so all we here can only speculate about.

regards and enjoy the music,
R.
Adam, Have you checked your turntable bearing? Now that your rumble is generalized, I am guessing you have either run out of lubrication in your bearing and/or your bearing is worn in some other bad way.
Rega tables do not have a ground wire.

Interesting. How do they get rid of the static charge that builds up on the record surface as the spinning vinyl platter "rubs" against the surrounding air molecules? It has to go somewhere otherwise it "sparks" to the nearest path to ground.

Before I realized the ground wire had fallen off, it sounded like a dirty record was playing (background noise) with the occasional "pop" caused by the arc to ground. I nearly tossed out a perfectly fine record thinking it was too contaminated to save.

Is it really rumble? Have you used a test record with various tones to identify your tone arm/ cartridge cantilever's resonant frequency? When my test record plays the resonant frequency, the entire arm/cartridge assembly visibly shakes. Have you moved any furniture or speakers in the room that might have affected the acoustic characteristics? If my speakers are too close to a corner, the bass can get boomy.
Once my ground wire fell off and I heard "popping" noises. As a record spins, a static charge builds up on the vinyl surface. Normally it would flow to the spindle, which is connected to the chassis ground and out. In the absence of a path to ground, the static would discharge to the cartridge itself. In your case I think it's a coincidence that it occurs as the cartridge nears the spindle, the record has been spinning for 10 to 15 minutes building up more static electricity with each revolution.
Check your ground wire.
Rich
"staccato-like popping" Can you guess in what frequency range? Rumble is very low frequency stuff, as the name suggests.
It's definitely not a "hum." The interference is a very irregular "staccato-like" popping type of rumble, which is now starting to bother me even at the outer grooves of a record. I removed and replaced the belt, moved the sub-platter up and down a few times within the bearing, checked the cartridge wire leads, checked the anti-skate, removed - cleaned - re-plugged the phono interconnects, ...... and still the problem continues, now anywhere along an LP's surface. Oy Vey !!
A la Casey's good idea, this speaks also to the question of whether you are hearing "rumble" or "hum". The power amp transformer could induce hum, not rumble.
Looking at your system photos I am struck by the fact that your problem area is directly beneath the power transformer of your amp.Why this would suddenly become an issue I have no idea.But the first thing I would try is to move the turntable two inches to the right (or the amp to the left).I would try this first because it would be so easy to do.I spent four hours last monday ridding my front end of sudden noise infestation,it can be maddening.When it's back to normal Life becomes so good.Good Luck.
To all who have replied with good ideas ---- Lewm, Stringreen, Halcro, Pops, Marakanetz, and Nick --- Thanks a lot for your advice. I'm going to spend some "quality time" with my table and try out what you guys are telling me. I appreciate all your help, and I will post what's happening as I proceed. This is a great example of why I enjoy being a part of the Audiogon community ! Happy Listening to all !
Dear Adam, I haven't a clue. Typical reasons for what you are hearing are that some cartridges can pick up EMI from some turntable motors. Thus, as the cartridge nears the center of the LP, it gets closer and closer to the motor until at some point, hum becomes audible. But this is "hum", not "rumble". Grado and Decca cartridges, IIRC, used to be culprits in this sort of issue (the EMI-induced hum, I mean). Rumble is hard to describe, except I think of it as low-pitched and irregular in frequency. Like Halcro and some others suggested, make sure that there is no mechanical contact being made between arm wand and chassis or platter or other parts of the tonearm, as it sweeps across its arc. Does the cartidge get all the way to the run-out grooves, or does it get hung up? If the latter, then it is some sort of mechanical problem.
Have you checked that the arm-lift is not touching the bottom of the arm when it reaches the end?
Some arm-lifts are not truly horizontal and if adjusted so that it has minimal clearance under the arm......can actually touch the arm?
..just a thought but the main bearing that holds the platter needs lubrication or replacement. That's what I would check first
Hi Lewm.....
As you requested up above, you can easily see my analog front end by clicking my system link. So, with all due respect, instead of telling us how Marakanetz's premise is flawed, can you please offer me some constructive advice as to what you may think about the problem I'm having. I would really appreciate your expertise. Thanks a lot.
Marakantz, With much respect, your last statement is a doozy (not a Deusie). Can you say why that would be? Would you say that the converse is true: a new phono stage is less sensitive to rumble? I don't think so. But it does follow from your premise, which should indicate the premise is flawed.
phono preamp as it ages becomes more sensitive to styli or vinyl surface imperfections and passes rumble.
Hi Pops.. First of all ... Thanks a lot for your compliment on my system.
No, I do not have another cartridge. The Exact 2 and RB-301 were bought together with the table. But I will follow your suggestion and try to adjust the anti-skate a bit. I'll keep you posted as to what happens.
Adam just jumped to your system page...nice! But I do see you are using a reba 301....do you have another cartridge you could try out?
Adam what tonearm do you have, the rega I had used a magnet to control the anti skate. For me it happened like you say...all of the sudden. The further into the outer grooves the arm/cartridge rode it started making a distorted sound and then would actually jump backwards a bit. I thought it was an A/S problem and could never solve, it also did not do it on every album but did on most.

I made several adjustments to the arm and could never solve the issue. I moved on to a new tonearm and cartridge so I do not know positivly what the problem was...even though I suggested it is a cart problem above for you, I am fairly certain my problem was with the tonearm and most likely A/S...
Lewm ..... all there... please click on my system.
Nick ..... I cleaned the stylus, but no improvement. For years, I've been cleaning the stylus after every listening session.
Marakanetz ..... as Pops says, why would the phono stage only cause a problem with the inner grooves ?
Pops ..... I just don't understand why a "stylus or tonearm problem" would happen all of a sudden like this.
Marakanetz what would the phono preamp have to do with noise only on a consistent part of the record?

It sounds more like a stylus or tonearm problem, I had a similar problem with a rega 300/blackbird towards the end of the record. It would start mistracking about the same place you mentioned, my guess is it was the cartridge but I replaced the cartridge and the tonearm so I never really solved the problem.

Tracking at the end of the record is very difficult for a cartridge/tonearm...my best guess is a stylus problem.
Did you try cleaning your stylus? It could be the result of vinyl residue built up on the stylus.
if it's not time for stylus replacement, than it's probably your phonostage needs service.