advertisement


LP12 arm collar r armboard bolt tension level

Mr Pig said:
Most of the bolts on the LP12 are best done up to the correct tightness. By correct I mean the tightness that wouldq typically be right for a bolt or screw of that type.

It's quite easy to demonstrate how to judge bolt tightness by feel but it's harder to explain over the net. But feel is the best way to do it. Yes, you can use a torque wrench, if you have one that is accurate at low values, but with little bolts and screws you can feel when it's right more easily with your fingers.

Find something you can practice on. I used to show people on an old bike stem. It doesn't matter what it is, the principal is the same. Thread the bolt or screw in until it 'lands', until it gets to the point where any more rotation is tightening it. From that point the majority of bolts will want about a quarter of a turn but you can feel it. The amount of resistance you'll feel for that quarter of a turn will feel constant and then it will get to a point where the resistance will start to change. Depending on the type of screw and what it's going into either you'll feel that much more force is needed to turn the bolt or, strangely, that it's turning more easily. What is happening is that either you're now starting to try and deform the materials or they are weak enough that they are failing easily. Either way, you are going to far and if you continue you risk damaging something.

As long as you don't strip the thing you can tighten up and undo a bolt lots of times getting a good feel for it. Then just translate that onto the bolts on the LP12 and you're good. It might feel strange at first as you don't think you're doing the bolts up very tight but you are. The tool is multiplying your force.

I said almost all of the bolts on the LP12, there are exceptions. The hanger and plinth mounting bolts on the standard top plate, do those fechers up proper tight! Because if you don't, they can come lose when you're tightening the spring and plinth fastening nuts. Especially if you're using very tight locking nuts. Both the bolts and nuts are steel so will take a good old tighten. If you're using an alloy top-plate I'd thread lock the rods into the inserts for the same reason.
Click to expand...
Apologies for the delay to reply. Was busy yesterday.

Thanks a lot for the detailed info. I don’t have a torque wrench that is accurate in smaller values. Only firm 2-25 Nm. So I’ll have to learn to do it by feel as you say, for each particular fasterner.

So the Arm collar bolts on the armboard are supposed to be much less tight than most of the other bolts? Certainly makes a big difference to the sound, but from listening I found the sound a bit too soft if they are too lose, although it’s very musical.

As I said before there are two different versions (and might be more) of the single layered double laminated MDF armboard. One is lighter and the other heavier. Any ideas why? Maybe the heavier one is less prone to deforming under pressure from those arm collar bolts.
 
The Lejonklou forum has members who use the same torque screwdriver and have experimented with different torque settings on every fastener for the LP12. They all use the Linn “tune dem” method to come to their conclusions.

You might be able to obtain some of the settings by using the search function. Most are under 2Nm. My experience found one setting for the Khan top plate to be below the lowest setting of the very same torque screwdriver used by Lejonklou members.
 
Colin131 said:
I said before there are two different versions (and might be more) of the single layered double laminated MDF armboard.
Click to expand...

I don't know exactly how many variations of the armboard there are. The very first one was just painted on the top. The next one had laminate in the the top but both of these were bare MDF on the underside which was stupid as the underside absorbed moisture, expanded and the board bent.

After that you had laminate both sides then a layer of laminate in the middle then two. On current boards the laminate is not as thick and strong as it used to be. How much is by design and how much is just different suppliers I don't know.
 
John said:
The Lejonklou forum has members who use the same torque screwdriver and have experimented with different torque settings on every fastener for the LP12. They all use the Linn “tune dem” method to come to their conclusions.

You might be able to obtain some of the settings by using the search function. Most are under 2Nm. My experience found one setting for the Khan top plate to be below the lowest setting of the very same torque screwdriver used by Lejonklou members.
Click to expand...
Thanks a lot for the info. It’s quite complicated! I’ll have a look at that forum to see what they say!

If I was to get a suitable torque wrench in the right range does anyone have any recommendation for one?
 
Mr Pig said:
I don't know exactly how many variations of the armboard there are. The very first one was just painted on the top. The next one had laminate in the the top but both of these were bare MDF on the underside which was stupid as the underside absorbed moisture, expanded and the board bent.

After that you had laminate both sides then a layer of laminate in the middle then two. On current boards the laminate is not as thick and strong as it used to be. How much is by design and how much is just different suppliers I don't know.
Click to expand...
Are you talking about only MDF boards? The early particle and plywood ones were the ones that were painted black weren’t they?

Yes I have seen an MDF with only top laminate.
I have tested before and don’t like the sound so much of the double and triple sandwich MDF boards, but maybe I was tightening up the arm collar bolts too much. I’ll try again soon.
The ones I like the sound of are the MDF ones with top and bottom laminate and a single layer in the middle. They sounded a bit more musical to me than the double and triple sandwich ones. This single layer type was made for a long time from 1989, but this type has two different types (at least) that weigh different amounts. One is about 40 grams heavier. Not sure if it’s a design thing or just a different company that made them. I bought several of each type and chose a lighter one to use as I’ve got the ittok, so thought any weigh saving on the suspension might help.

So you defo recommend not doing up these arm collar bolts tight? Only just snug or sinking in the MDF a bit. The sound is more musical for sure when they aren’t right. I guess this is Linn’s “lossy” technique, and same went for the armboard screws.

Then then abandoned this lossy regime with the Keel, Kore etc. Why was that? If they endorsed it before?
 
My theory : the answer to your question is because fortunately chaos rules, not order. We all like to think that engineers, doctors, lawyers etc. all know exactly what they are doing and follow their , inevitably expensive, master plans. But said plans don´t really exist or only in part and so called professionals of a scientific bent just react to ever changing materials and tools and circumstances and occasionally strike lucky. Lossy solutions just mean that the real problem further back upstream hasn´t really been solved in its entirety. Now with the Radikal motor and control and a Karousel stuck in a Keel the problem of resonances created by the old motor reaching the cartridge /groove interface have been controlled to a much greater extent so that means one lossy solution fewer needed and a lot more income generated. Now , what to do with us lesser mortals and less well-heeled who still have armboards ? Personally this year I have reached the conviction that the real culprit to be exorcised is the belt as a transmitter of remaining resonances that still find a way though to the tip; hence the startling effect the blue belt has had, in my mediocre opinion and system at least - it has shortcut all the Linn upgrading mumbo-jumbo to a considerable extent, not really appreciated by those who already had "superior" sub-chassis and DC motor equipped systems and subconscious interests in ignoring the importance of the belt. For me and mine, its the player of the year 2022 and I hope someone improves on it in the future and at a similar price.
 
Colin131 said:
If I was to get a suitable torque wrench in the right range does anyone have any recommendation for one?
Click to expand...

Ones that are accurate down that low tend not to be cheap. Mine cost about £130 I think, might have been more, but I bought it for carbon bike parts. I don't feel it's necessary for an LP12. Doing it by feel is perfectly sufficient.

Colin131 said:
So you defo recommend not doing up these arm collar bolts tight? Only just snug or sinking in the MDF a bit.
Click to expand...

That's what I do. The Linn arm collars have castled washers so they are not going to loosen off. Like I say, if you crank all bolts on the LP12 up really tight it sounds shite!
 
Mr Pig said:
Ones that are accurate down that low tend not to be cheap. Mine cost about £130 I think, might have been more, but I bought it for carbon bike parts. I don't feel it's necessary for an LP12. Doing it by feel is perfectly sufficient.



That's what I do. The Linn arm collars have castled washers so they are not going to loosen off. Like I say, if you crank all bolts on the LP12 up really tight it sounds shite!
Click to expand...
Thanks for the info. I will really remember this about the arm collar bolts. It does sound much better when they aren’t very tight. How about the armboard screws? Same thing?

I will leave the torque wrench then, thanks for the advice.
 
Chris said:
My theory : the answer to your question is because fortunately chaos rules, not order. We all like to think that engineers, doctors, lawyers etc. all know exactly what they are doing and follow their , inevitably expensive, master plans. But said plans don´t really exist or only in part and so called professionals of a scientific bent just react to ever changing materials and tools and circumstances and occasionally strike lucky. Lossy solutions just mean that the real problem further back upstream hasn´t really been solved in its entirety. Now with the Radikal motor and control and a Karousel stuck in a Keel the problem of resonances created by the old motor reaching the cartridge /groove interface have been controlled to a much greater extent so that means one lossy solution fewer needed and a lot more income generated. Now , what to do with us lesser mortals and less well-heeled who still have armboards ? Personally this year I have reached the conviction that the real culprit to be exorcised is the belt as a transmitter of remaining resonances that still find a way though to the tip; hence the startling effect the blue belt has had, in my mediocre opinion and system at least - it has shortcut all the Linn upgrading mumbo-jumbo to a considerable extent, not really appreciated by those who already had "superior" sub-chassis and DC motor equipped systems and subconscious interests in ignoring the importance of the belt. For me and mine, its the player of the year 2022 and I hope someone improves on it in the future and at a similar price.
Click to expand...
Thanks for the info. The lossy solution is making more sense now after your explanation.

The thing is. Do I want my LP12 to reproduce exactly the record as it was mastered and cut? Well sometimes yes but also no as well. I listen to a lot of 80s and 90s stuff.A lot of digital recordings and A/D and back transfers, that suffer from digital edge, even on vinyl. If my LP12 is totally accurate I’ll hear all that edge, which clearly wasn’t what the original intention was and therefore isn’t accurate in that regard. I’m not saying an older LP12 somehow miraculous does a backwards engineering process accurately and gives you exactly what the sound should be like in this case, but it can help in certain aspects. A pre cirkus deck can reduce digital edge due to its sweetness and warmth in the mid and top end and make the sound appear a bit more natural with such material. That’s a really useful thing with some records.

So someone like me is unlikely to enjoy the latest LP12s. I didn’t like the cirkus decks and I tried them many times. The latest ones that are further that way towards accuracy are likely to be worse for me.

Of course on some records more accurate replay (in terms of reproducing the sound at the record mastering/pressing location) is desirable, but that’s not the bulk of what I listen to.
 
Last edited:
Mr Pig said:
Yeah. Tiny screws. Just nipped up enough to hold the board still. Crank them any more and the wood just strips.
Click to expand...
Thanks a lot. Which other ones should I also not have too tight? 2 Nm and under? Is it just the arm collar bolts or are there any more?
 
Colin131 said:
Which other ones should I also not have too tight? 2 Nm and under? Is it just the arm collar bolts or are there any more?
Click to expand...

All of them except the hanger bolts to the top plate. Tighten the cross brace bolts too much and you dent the top plate. Motor mounting bolts you'll round the heads and struggle to tilt the motor. Arm pillar lock bolt, ask an Akito owner. It's all just common sense over any stupidity the internet might say.
 
Mr Pig said:
All of them except the hanger bolts to the top plate. Tighten the cross brace bolts too much and you dent the top plate. Motor mounting bolts you'll round the heads and struggle to tilt the motor. Arm pillar lock bolt, ask an Akito owner. It's all just common sense over any stupidity the internet might say.
Click to expand...
That’s great thanks for the info. I need to check them on the LP12 I have now. In the past I went too far on the crossbrace bolts on another LP12. Damaged the plinth slightly!
 
I know some people have optimum torque settings for each LP12 fastener but I'm wondering does anyone know the optimum torque for the nuts that hold up the suspension springs?
 
As much as it takes to get the platter to the correct height and level!

It's not about torque with these, the nyloc or alternative is just to keep them in place.
 
I can't believe everybody is suggesting that all three arm collar bolts need the same torque. The ratio, orientation and aggregate of torques is critical to musicalityfulness. You boys have a lot more experimenting to do. Amateur. Shocking, even.

;-)
 
Also you must make allowances if you’re assembling an LP12 in the Southern Hemisphere. The fact that water circulates the drain in the opposite direction south of the equator means the torque settings must be adjusted accordingly. I saw in on an episode of The Simpson’s years ago so it must be true 🤣
 
You must log in or register to reply here.


advertisement


Back
Top