Linn LP12 Bouncing Eratically During Playback

braxus

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#1
It wasn't bad before, but since I'm able to play records again, I'm having problems with my platter bouncing, or more like shuddering, during playback. This causes the cartridge to bounce with it and skip across the record. It never used to do this. My music today was not loud at all, so it can't be from the speakers. And I put the lid down and walked away from the table, and it still was doing it. What is causing this? I was shown some ideas to help reduce vibration on this table, which I may implement. But I'm not sure they will help much. I was shown a base board for better damping, a better platter matt, and use of possibly some cones on the bottom. I don't know where the platter is picking up the vibrations, but it almost seems like its coming from the table itself.
 

braxus

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#3
Nope. Its been sitting on my rack for months. Granted its been to the stereo shop a couple times before that and he did adjust the suspension in it, but it was working fine after he did that.
 

Gepetto

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#4
It wasn't bad before, but since I'm able to play records again, I'm having problems with my platter bouncing, or more like shuddering, during playback. This causes the cartridge to bounce with it and skip across the record. It never used to do this. My music today was not loud at all, so it can't be from the speakers. And I put the lid down and walked away from the table, and it still was doing it. What is causing this? I was shown some ideas to help reduce vibration on this table, which I may implement. But I'm not sure they will help much. I was shown a base board for better damping, a better platter matt, and use of possibly some cones on the bottom. I don't know where the platter is picking up the vibrations, but it almost seems like its coming from the table itself.
Does it do it with the pre volume turned all the way down? Try that to eliminate the acoustic feedback possibility or listen with headphones to see if it still does it.
 

roccus

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#5
I like this idea.... headphones

Does it do it with the pre volume turned all the way down? Try that to eliminate the acoustic feedback possibility or listen with headphones to see if it still does it.
 

62vauxhall

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#6
The TT looks to have a two piece platter. This may sound like a dumb idea but I'd take the main platter off and try playing a record on the just vestigial platter portion that the belt drives. A record clamp could be useful or maybe play a 7" instead of 12" Might indicate a bearing / friction issue if less mass in motions decreases the symptoms.
 

stuwee

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#7
Hey Scott, I have no idea what could be wrong, the Linn is a awesome TT, right up there with the Thorens they cribbed the design from way back when. I think something must have been wacked on one of the moves you did with it, have someone check the spindle shaft too! And the motor mount from the base on it. Good luck buddy, very nice table :happy3:
 

marcok

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#8
http://forums.linn.co.uk/bb/showthread.php?tid=934&page=2
Reading this article I think the problem is related to a poor set up .
4 days ago I have just made a set up of my LP 12 , but it's not a simple thing .
Anyway I suggest you to check the horizotal aligment with a level .
In the web you'll find all set up the procedures for LP 12.
What's your arm ?
Ciao
Marco
 

Northwinds

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#10
A leveling issue should not make the cartridge jump like that. Never did with any Thoren's type I ever had. Something else is going on with the spindle, inner platter or something. Are all the mounts tight for the inner mechanism/inner platter?
 

stuwee

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#12
A leveling issue should not make the cartridge jump like that. Never did with any Thoren's type I ever had. Something else is going on with the spindle, inner platter or something. Are all the mounts tight for the inner mechanism/inner platter?
Thanks Ron, great minds think alike, *pats back, while patting yours*

Hey Lee, maybe you could get Stephen in touch?
 

bill7621

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#13
The TT looks to have a two piece platter. This may sound like a dumb idea but I'd take the main platter off and try playing a record on the just vestigial platter portion that the belt drives. A record clamp could be useful or maybe play a 7" instead of 12" Might indicate a bearing / friction issue if less mass in motions decreases the symptoms.
I'd look at the bearing.
 

marcok

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#14
A brief summary of Linn set up .
just made 4 days ago :
-adjust the 3 springs to level the arm base with the chassis
-check vertical bouncing
-check the arm movemonts ( V and H )
-check the horizontal level
-replace the oil of the ball bearings , if neceassary .
-check the belt aligment mounting the platter reversed to see the belt and pulley
-check the zero of the arm moving counter weight and without antiskatig
-check vta and vtf .
-adjust antiskating .
From here it's the best I can do .
Ciao
Marco
 

orange

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#15
Turn the volume OFF and try again.

And don't walk near it or step for a bit.

If that works you need to eliminate the transfer of vibrations, isolate the table, elevate/move the speakers or remember that you have a Phase Linear and are a Thunder God, not a mere mortal.

Realization may occur soon or else it's back to setup.
 
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marcok

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#17
Braxus ,
LP12 is more critic than Thorens . My father has a Thorens TD 145 .
My arrangment is different , because I use a special table designed for LP 12 .
My cart and and arm are the same . Anyway try to modify the resonance frequency
of your system inserting a piece of plywood between TT and rack or inserting a piece of wood
between the rack and the wall .
Ciao
Marco
 

marcok

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#19
Ron ,
you are probably right , but I have suggested plywood because my table has a plywood sheet .
and for a test is easier to find it .
Furthermore I have suggested to insert a piece a wood between rack and wall , just like
the arrangment of my father's TD 145 .
Ciao
Marco
 

stuwee

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#20
Hola Scott, there is something wrong with your tonearm, I have no idea what, that 'shudder' from the cartridge is very wrong. most folks would say it's the Lp you were playing was pressed badly. I have a few that I noticed the same action on. If it does this on several that you play and never noticed it before...Bad!

So my amended advice is to check the spindle and now, have your arm looked at as well, good luck!
 
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