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84 Linn LP12 Suspension

If your intention is to find a shortcut to suspension Nirvana (pun), disconnect the tonearm cable from the base of the tonearm (there is a tiny grub screw holding it in) and, whilst lying on the floor with your head beneath the deck, ensure that each spring and top grommet assembly aligns with each suspension bolt as per the image below.

Those that aren't centred can be made so by rotating (not twisting) both spring and top rubber grommet either clockwise or counterclockwise until centred. Take particular care so as not to put any spring(s) under additional rotational tension as per the following setup manual instruction.

"If you find that the suspension refuses to move freely, it may be that one or more of the springs was twisted and failed to come back to the relaxed position when you turned it to adjust the chassis position. If this is the case, you can reach up and pull the spring down from the top grommet to release the twist; this should stop the erratic behavior of the suspension."​

If performing these adjustments whilst observing from beneath, you will quickly get a feel for how the whole suspension rotates with. This is because you are actually changing the direction of lean, albeit slight, of each spring.

susp_t1.gif
 
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Craig B said:
Iensure that each spring and top grommet assembly aligns with each suspension bolt as per the image below.
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This assumes the spring bolts have been set vertically in the first place.

I would just go straight to trying to set the bounce. Much else and you'd be as well doing a complete rebuild.
 
Tony L said:
FWIW I always ran my LP12s without the baseboard/‘soundboard’ on the bottom. I used four little cut down plastic washers of the right thickness so the rubber feet still sat square when screwed back on. The deck does sound better with that source of resonance removed. ....................

PS As others have mentioned do be aware there is live electricity in there. I can say that with absolute confidence!
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I use mine without the "fibreboard" base - I cut four small triangles of board and PVA glued them in place to keep the feet stable when they were screwed back in place.
 
Mr Pig said:
This assumes the spring bolts have been set vertically in the first place.
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Yes - I noticed my top plate was bowed slightly, downwards, as seen next to the armboard. Internet told me this was deliberate, to splay out the two right bolts/springs in order to add slightly more stability...

in which case, centring the springs will be hard to keep in place since the grommets are square cut...

small amounts I know - but could see it going off if transported...
 
robbyd said:
Yes - I noticed my top plate was bowed slightly, downwards, as seen next to the armboard. Internet told me this was deliberate, to splay out the two right bolts/springs in order to add slightly more stability...

in which case, centring the springs will be hard to keep in place since the grommets are square cut...

small amounts I know - but could see it going off if transported...
Click to expand...
Internet should have told you that this is a result of the top plate being supported on three sides only, whilst also being under tension via the two bolts that clamp it to the plinth via the blocks and metal cross-brace (it is also an intentional tight fit between the front and back plinth recesses).

With benefit of hindsight, Linn eventually got round to claiming this to be an intentional design element that prevents the top plate from resonating at low enough frequencies that might bypass the suspension. Well, they would, wouldn't they. Basically, they wanted a long enough tonearm board that allowed fitment of the once common remote tonearm rest.
 
Mr Pig said:
This assumes the spring bolts have been set vertically in the first place.

I would just go straight to trying to set the bounce. Much else and you'd be as well doing a complete rebuild.
Click to expand...
As you well know, Colin, along with levelling the suspension, this is how a bias toward vertical oscillation (i.e. 'bounce') is achieved. There is no other 'setting the bounce', all that is subsequently left is an attempt to not upset such whilst routing the tonearm cable.

I am sure that you can do this all in your sleep, what is somewhat more difficult is describing it in a way that someone else who is less experienced can follow through to a successful outcome.
 
Craig B said:
Internet should have told you that this is a result of the top plate being supported on three sides only
Click to expand...

yes - it's a very thin plate and unsupported not the best idea... in fact, seeing inside one (80s), it's pretty obvious how things can (and probably have now) be improved...
 
robbyd said:
I noticed my top plate was bowed slightly, downwards, as seen next to the armboard. Internet told me this was deliberate, to splay out the two right bolts/springs in order to add slightly more stability...
Click to expand...

The internet is wrong. The three bolts should be vertical. Linn supply a special tool to do this. Once the top plate is dished and bolted to the plinth you level the plinth and set those bolts vertical. It's not easy to do without the tool but it can be done. Unless you want to strip the deck you have to just go on the assumption that the dealer did this when he set the deck up. It can be really difficult to get the thing set if the bolts aren't right but you might be lucky.

Craig B said:
There is no other 'setting the bounce', all that is subsequently left is an attempt to not upset such whilst routing the tonearm cable.
Click to expand...

You mentioned rotating the springs to center them but the point of rotating the springs is to balance them against each other. Might take minutes. might take flippin ages! Worst case is that you need to swap them around but if this deck was set up properly in the first place it should come good.
 
Mr Pig said:
Don't mess with anything else until you've at least read the set up manual. If you just randomly change stuff you could end up having to redo the whole deck from scratch.

The nuts which adjust the springs are to set the height, to level the platter/sub-chassis to the plinth. They're not for setting the bounce. If you've moved them you'll have to re-level the deck.
Click to expand...

Ok there was a bit of confusion here in my wording. I didn't end up loosening the tonearm bolts, but did adjust the bolts which hold the tonearm board to the chasis since the tonearm board was not centered -- now it is.

Someone local was kind enough to lend me a jig so I'm working my way through the cymbiosis manual now. I really would not like to reassemble the entire deck, but just get this suspension right. The bounce has already gotten better by messing with the springs, but it's not there yet. I will post a before and after video when I am done. The Swain guide has been very helpful. If I can't get it right, I will send it to the local dealer, but would like to learn to do this myself if I can.
 
My amps are getting recapped so I have some time to keep fiddling with this while the jig is on loan. Here is a before and after video. I think I got it mostly right at this point. The screws look as centered in the grommet as far I can see -- it's hard to see clearly through them though. The platter is level and the armboard is flush with the plinth. I was having some issues with a rock left and right which seem resolved. What do you all think? Thanks for all the help you all have given me!

Before:
https://streamable.com/irs1qq

Now:
https://streamable.com/3311wa


EDIT: Honestly, a little more tuning, and the bounce has gotten more even and holds for longer time. I think it's set. But still look forward to thoughts.
 
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Tony L said:
The LP12 setup manual can be found here. The tonearm mounting bolts have no impact on the turntable’s bounce, they are an entirely different thing. Start with the manual. Read it several times and the design concepts and setup techniques should become clearer.
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FYI, there is a more up to date Linn LP12 setup manual available on The Vinyl Engine website if you have a login.
 
That looks good, I'd be happy with that.

If you moved the arm board I'd check the alignment of the cartridge again.
 
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