LP12 Footfall Problem Fix

Posted by: Greg Beatty on 15 May 2003

I'm almost ashamed to admit that I did this, but it is allowing us to play vinyl again.

My LP12 is currently sitting on top of a television Eek and due to the arrangement of the room still being in flux, I am not at liberty to wall-mount it at this time.

Trouble is, even with a 275 lb TV under it, the LP12 skips like mad when anyone walks near it. So there hasn't been any record playing in the house for quite some time.

I read a post a few weeks ago where the poster mentioned that he sold his LP12 and got a Rega (P3, P9 maybe - I don't recall) and in addition to the other things he liked about it, it solved his footfall problem. This got me thinking.

I think of the LP12 suspension as a way of *isolating* the turntable, but it seems if the LP12 gets a shock at a very low frequency (like a footfall), this sets the suspension a bouncin' and bad things happen. So what would happen if I "froze" the LP12 suspension???

So I did it. I removed the baseboard (this was already removed actually) and put a properly sized rock under the bottom of the bearing. The height of the rock is such that the the platter lets the suspension drop the platter and the armboard, but it hits the rock before it bottoms out. If the rock is too high and keeps the platter from dropping at all, then the belt comes off the inner platter.

Now the platter/armboard is kindof teetering on the bearing. So I folded up two pieces of paper and placed them between the armboard and plinth at either end of the armboard. Now the suspension is "locked" in three places.

Viola!!! We have vinyl again - you really have to jump near the LP12 to get it to skip now. Not the best solution probably, but the LP12 in this setup still pees all over the Sony ES series CD player I'm using.

Thoughts? Is there a better way to do this?

- GregB

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Posted on: 15 May 2003 by ejl
Although I don't want to doubt what you say about it still sounding o.k., I would think that the rock is transmitting vibrational energy directly to the bearing and into the platter.
Posted on: 15 May 2003 by JeremyD
There's probably someone on the forum who has an unwanted Trampolinn, and is willing to pay you to accept custody of it. It might well help.

Alternatively, you could try it on a light, rigid coffee table - the lighter the better - the sort of thing that Linn recommended before the days of dedicated stands (not to mention 275 lb TVs).

Finally, you could try tracking your cartridge at the top of its permitted range.

Sorry, that's the best I can think of.

--J

[This message was edited by JeremyD on THURSDAY 15 May 2003 at 15:59.]
Posted on: 15 May 2003 by Greg Beatty
J -

"Alternatively, you could try it on a light, rigid coffee table"

With a 3-month old in the house who will be toddling before I know it, this option isn't feasible for us. Also, I don't know if the 'Lack' table solution addresses footfall problems.

As for feedback issues, is there a better way to do this? I remember someone using three sorbothane thingies in place of the springs to similar effect.

- GregB

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Posted on: 15 May 2003 by JeremyD
Yes, big Sorbothane feet might help too - but do check that the feet are suited to the weight of the LP12. Like the Trampolinn they should only be used if normal support methods cannot be used.

Re three month old: perhaps you get one of those "cages" that some people use to keep babies and toddlers in a safe area? No, not to put the baby in - to surround the LP12 on its stand, preventing baby from getting near the danger zone.

--J
Posted on: 15 May 2003 by Greg Beatty
J -

Thanx for the idea. We have already got some cage thingies, I suppose if the LP12 were in a corner and we used two cage thingies...

Also keep in mind that my hi-fi setup is, um, very "real world" (read: compromised). There is a bigg'un TV between the speakers that itself is a large, resonating box that has speakers in it. So a little extra bloom in the bass via feedback may not be as noticable in my already-hobbled setup.

- GregB

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Posted on: 15 May 2003 by Paul Ranson
quote:
Trouble is, even with a 275 lb TV under it, the LP12 skips like mad when anyone walks near it.

'Because' rather than 'even'.

A Trampolinn may well fix things, otherwise a Lack. Assuming that your furniture and floor aren't wobbly beyond normal wobbliness, in which case lifting the carpet and getting the nails out would be necessary. (Or perhaps your house is falling down and if you don't fix it the system will end up in the basement...

Paul
Posted on: 15 May 2003 by Greg Beatty
...OK. So a lightweight table might help. I will see if there is something in the house I can try.

- GregB

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Posted on: 15 May 2003 by seagull
I second the cage suggestion. When Seagull junior was young we used a fire gaurd to protect the hi-fi.

It got very strange looks from visitors but prevented little hands playing with the large inviting knobs on the amplifiers as well!
Posted on: 15 May 2003 by JRHardee
Greg--
You're welcome to drop by and borrow an old (really old) Sound Org table.
We have heinous footfall problems. We tiptoe thru the living room. Problem solved.
Posted on: 15 May 2003 by gordon cavanaugh
i had the same problem when i moved to a house with bouncy wood floors.
my lp12 sat on top of a 5 or 6 tier solidsteel rack. if you walked
within 6 feet of the lp12 the arm jumped. i put the lp12 on an audiotek
wall shelf, and this solved my problem. recently, i replaced the solidsteel
with 2 4 self quadraspire racks. for grins and aesthetics, i tried the lp12
on the top self of one of the q-racks, and i have no needle skipping, arm
bouncing problems.
Posted on: 15 May 2003 by Greg Beatty
Hi John -

I may take you up on your offer.

Let me find a table in the house that can stand in as proxie to see if it solves the footfall prob first.

What sistem are you up to now? I'm running Nait 5/Allaes.

- GregB

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