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The LP12 Bolt Mod

This is intended to replicate the fairly recent change that Linn themselves have done, connecting the top plate to the corner brace nearest the motor.

I got the idea from discussions over on Pink Fish Media, though most of the info has disappeared now, as it was on the old forum.

Anyway, the first idea was to drill a hole in the top plate, and simply drive a screw down into the corner brace from above. Nice and simple, and has the benefit of being able to alter the amount of tension used. The shame is that the screw is visible.

So here's my take on it.

What I did was bond a washer to a flange nut (also known as drive in nuts) (the things that are used for mounting loudspeakers in cabinets). This gave me a nice long thread for the bolt to connect to.
I think I used UHU extra strong glue (in the yellow and black tube). But then I used JB Weld for the other join, so I'd just use JB Weld for the lot. Great stuff - get it from Halfords.
I then removed the baseboard from the LP12 (obviously secure the arm (in my case the Aro just lifts off), remove the outer platter and lid before moving!!).
My LP12 jig is two small tables on top of a large one, just the right distance apart from each other to let the LP12 rest between them.
I then drilled a hole in the corner brace, then threaded the bolt through the hole, and ran a nut down the bolt so it was on top of the corner brace. I bonded the washer/nut to the underside of the top plate, threading the bolt into the flange nut to locate it correctly, and screwed the nut down towards the top of the brace to give some upwards push while the JB Weld was going off.

I've recently received an email asking what size bolt to use.
I don't recall, and don't fancy crawling under my LP12 just to check. To be honest, I recommend you measure the distance yourself, and at the same time you can get an idea of what you're letting yourself in for - it's fiddly, but not difficult.
What you're looking for is the right length that will thread onto the flange nut when in position without hitting the underside of the top plate, so you maintain the tension. You may need to pack the bolt down with a washer under the corner brace to get the length right, though I didn't.
However, for those who worry about these things, I went and poked around in the workshop, and I think the one I used was a 50mm M5.
Obviously you'll need to make sure that you get an M5 flange nut as well - you tend to find them at loudspeaker parts suppliers - Maplins may do them. I use CPC for a lot of my bits (see part number LS01631), but if there's a Maplins near you, then so much the better.

Oh, and on the subject of tension - the consensus seems to be not too much - certainly don't go tightening it up so much the top plate starts bending.

Here's the pictures

LP12 bolt - the plan - 5 Oct 2003
Here´s the flange nut bonded to a washer to increase the surface area, plus the bolt itslef, and my plan of how it will fit. In fact, it ended up much simpler....
LP12 bolt mod 1 - 13 Oct 2003
Here´s the bolt in position, viewed from the side. You can just see the grey JB Weld used to bond the flange nut to the underside of the top plate oozing out.

LP12 bolt mod 2 - 14 Oct 2003
Hereīs the bolt in position, photographed from directly beneath. Not sure if the postion is exactly that used by Linn, but Iīm sure itīs fine. It could perhaps be a bit closer to the motor...
LP12 bolt - from above - 15 Oct 2003
Look mum, no holes! Top plate has remained intact.