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LP12 Set-up - a brief overview.
2011-02-06, 15:06 (This post was last modified: 2014-06-11 14:31 by Cymbiosis.)
Post: #1
LP12 Set-up - a brief overview.
I am starting this thread in response to a growing number of requests from owners who perhaps live a long way from their Linn Specialist Turntable Retailer and require a set-up of their LP12. This is merely a guide, and in my opinion you are obviously far better seeing your dealer for any work that you require. It follows that I or any other participating members do not accept any liability whatsoever for works attempted following your reading of any information contained here. As I said, hopefully you will see this as a general guide and you will hopefully gain a better understanding of the setting up process and consequently a better idea of why retailers need to charge a little for the time and expertise they spend on setting up your LP12, and also why they are the best people to set-up and get the best sounds from your LP12. Care, experience, expertise and attention to detail are paramount.

Within this guide, please feel free to post questions and offer additional advice wherever you like. All I would say is let’s try and keep it to the point and as on topic as possible if we can, as this will make it more readable for anyone interested in using the thread for reference in future. It’s not going to be completely all encompassing, so if be very happy if any of you wish to chip in and raise points as we go along.

Kind regards,

Peter Swain

With any process or call it a journey if you like, one needs to start somewhere and I think the best way would be from the ground up and at component level, so you can pick up the relevant information at whatever point you wish. I also think pictures are often far more useful than just the written word in conveying the salient points.
So, let’s start with the plinth and what’s important when checking the top plate when fitted:

Plinths come in various finishes as we know and older ones lack the corner-braces. These stiffen up the plinth, help to minimise warping and also corner-braced plinths sound better.

[Image: zeml.jpg]


There are two obvious differences between top-plates that you are probably aware of: The older non studded top-plate and the more recent top plate which has a stud welded to its motor corner. Why? Well, it’s of critical importance that the top plate in the motor corner does not rattle against the plinth as this has dire consequences for the sound quality. Often this is missed and so people are just unaware of the music they are missing out on as a consequence! The addition of the corner bolt makes life easier to ensure there are no corner rattles present. It does not IMHO make for a better sound than say a well fitted older non-studded top-plate.

Older non studded top-plates can have either imperial threads cut for the two motor speed adjustment (tilt) screws, or more likely the more modern M3 threads. How do you tell? Well normally the imperial ones are dull silver cross-heads, later M3 screws are black cross-heads and the modern ones used on the deck are bright silver posi-head. Additional to having imperial threads, very early top-plates can have these two threaded holes non – equi-distant from the motor pulley hole, thus giving dealers two problems to overcome if fitting a Radikal, as off-set holes would mean pulley to sensor bracket contact, and also any attempt to screw the M3 Radikal speed sensor screws in to secure the bracket will end in disaster as although they will start to thread up, very quickly the screws will seize up in the threads and will shear if forced!

[Image: y0lqe.jpg]


If there is just an imperial thread problem to overcome, then this can be overcome by carefully re-tapping the imperial thread out with an M3 tap. In engineering terms, not that great, but I’ve done more than a dozen now without any problem and the remaining new M3 thread is easily up to the job required of it.

If the speed adjustment screws are off-centre like in this picture above, I wouldn’t re-drill the holes. I’d pension off the top plate, save the hassle and use a new top plate as they are relatively low cost.

Top plate bolts. Silver pre-Nirvana ones and their non locking nuts should be discarded in favour of the far better newer black mushroom headed M5 bolts. Most are posi-head but in the last year or so they have become Allen head – This makes tightening them up with the M5 nylock nuts far easier.

When fitting any top-plate to a plinth, ensure the left edge is as straight as possible. Hold it up and look along the edge and ensure this is so. If not, correct it by careful bending. The stainless steel top is really quite soft and so it’s easy to overdo things, so check every step of the way – gently! If the top plate is raised at the centre where the two toplate screws and the two top plate bolts pull it down, then this is fine as it should pull flat once these are tightened.
Start the two top plate screws and tighten to within 1mm of the top plate, then what I do on a carpet with the motor side of the plinth wedged against my knees, is pull the top-plate (armboard end) towards me and hard against the plinth. Thus forcing the top-plate into the plinth as far as is possible and at the same time tightening the two top-plate screws. Beware overdoing this, as/or if the screws keep turning you should remedy this by initially changing the 6 x ½ Supa pan self tapping screws for 6 x ¾ Supa pan screws. Also beware slippage on the screw heads when tightening as if you do slip suddenly with the screwdriver it’s a big scratch you could end up putting in your top-plate!

For the cornerbolt/studded top plate one can now fit a mudguard washer and a M5 Nylock, and then start to “nip” it up whilst giving it the knuckle tap test on the top of the top-plate in the motor corner. It doesn’t want to be tightened up hard as the top-plate will deform and the deck would sound rubbish – just enough nipping on the nut to stop any rattling in that corner and no more.

For the non-studded top plate, one hope’s there are no rattles in that top corner. If there are, repeat the process until you get it right. Do not cheat by using adhesive in the corner as the deck will sound rubbish. Just top-plate tension is what you want to stop top plate rattles.
Areas on the top-plate rattling other than the motor corner are not particularly good news, and so you should attempt to minimise these wherever possible. For example if the area near the switch rattles, it looks and feels horrible, so it’s best to sort it out before you go any further.

Once you are happy with the top-plate and plinth union, proceed to the jig and gently clamp the plinth in to place ensuring the bottom edges are contacting the support surfaces. (Note. Older Afromosia decks may be smaller and so not supported properly by these surfaces! If so, just pull these plinths off-centre so that they can at least be supported by some of support surface and watch for slippage while tightening the clamps – I will take and post a picture of the next one I see, so as to explain this better). Once clamped level the plinth with a 15-30cm spirit level (not a small round one please) and check level on all four surfaces.
[Image: o1cu.jpg]



We are now ready to check that the spring bolts are hanging vertically.

Hardly brief, but abbreviated as compared, to what I could have written.

Comments please?

Ok then, returning to the point above about older fluted plinths sometimes being slightly smaller and being difficult to clamp in the jig I took a couple of pictures earlier this week to show you the problem and how I overcome it. Yes, if the jig's plinths supports were a little wider we would not have an issue, but just pulling the plinth so as it sits in a diagonal fashion rather than square in the jig works pretty well. Once clamped in place, please re-adjust the jig so as the four sides of the pinth are once again level.

Here is a small Afro plinth and as you can see - I hope! The lower plinth support on the jig isn't in contact with the flat edge of the plinth and so as you try and tighten the clamps they will start to ride up the bevelled edge of the lower part of the plinth:

[Image: p11005111.jpg]

By just shifting the plinth over to a more diagonal position, one will at least let the plinth allow the support rails to do their job in part as you can see in the image below, and allow you to clamp up, where before you'd struggle! Not perfect, but workable. Just ensure the jig's feet are now adjusted so as the plinth is level again.

[Image: p11005121.jpg]

Fettling LP12s since 1980
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2011-02-06, 16:03
Post: #2
RE: Setting up your LP12 - a brief overview.
This needs to be made a sticky.

So far very informative.
How are you supposed to deal with 'pockets' of top plate rattle once the motor corner is secure and free of rattle? It seems bending the top plate to try to erase these errors can only make it worse as it may not (& Likely not) be the top plate.
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2011-02-06, 16:30
Post: #3
RE: Setting up your LP12 - a brief overview.
(2011-02-06 16:03)eye-fi Wrote:  It seems bending the top plate to try to erase these errors can only make it worse as it may not (& Likely not) be the top plate.

Well, this is exactly the point. There is a knack to it yes, but mainly it's care and experience involved in what to do. Once one starts to see what's involved with LP12 set-up, people may become even more convinced that a visit to their dealer is their best course of action. Equally those who feel it is within their capability and cant visit, or find it very difficult to visit, their dealer, now have some advice in what is important in the set-up procedure. I've said many times, its not rocket science, just care and attention to detail. Experience, patience and enough time to set-up properly.

So much is made of getting the bounce right. However, this is just one of many important things to get right when getting the very best out of an LP12.

I regularly have people saying LP12s go out of tune easily - Nope, not if set-up is done properly.

I have had in the past people come to me having had LP12s in the past and moved onto other decks, often costing more than the LP12 saying the LP12 was not as good. My immediate offer is always: Please bring along your deck if you wish, for a comparative demo! On every occasion where this has happened (as far as I can remember) the LP12 has sounded better than what they have moved onto! In all occasions that I can think of, these owners now have an LP12 again!Cool

KR

Peter

Fettling LP12s since 1980
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2011-02-06, 17:47
Post: #4
RE: Setting up your LP12 - a brief overview.
(2011-02-06 15:06)Cymbiosis Wrote:  For the cornerbolt/studded top plate one can now fit a mudguard washer and a M5 Nylock, and then start to “nip” it up whilst giving it the knuckle tap test on the top of the top-plate in the motor corner. It doesn’t want to be tightened up hard as the top-plate will deform and the deck would sound rubbish – just enough nipping on the nut to stop any rattling in that corner and no more.

Thank you very much that you share your knowledge with us. I have a great respect that you try to explain things which are very difficult to discribe because the deep knowledge is taken out of your experiences of fitting an LP12 over many years.

To my question:
Are there any differences between the old (AC) and the new (DC) LP12 Motors in "fixing" the cornerbolt? The DC motor doesn't rattle and its vibrations are better isolated.

Thank you Rille
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2011-02-06, 18:28 (This post was last modified: 2011-02-06 18:30 by Cymbiosis.)
Post: #5
RE: Setting up your LP12 - a brief overview.
I'll be covering that soon Rille.

I've reported myself to HQ on the tread and if its considered ok to proceed with the overview, then I will.

KR

Peter

Fettling LP12s since 1980
Tel 01162 623754
Email - peter@cymbiosis.com
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2011-02-06, 20:43
Post: #6
RE: Setting up your LP12 - a brief overview.
This is an excellent thread, Peter, and IMO, should only be encouraged (if HQ agree, of course). I rebuild motorcycle engines now and again, so it's not as if I don't know one end of a torque wrench from another, or how to read an instruction manual, but I am about as likely to take my LP12 apart as I am to try brain surgery on myself. However (nerd alert! Wink ), it does no harm at all to know how and why something should be assembled in a particular way, and the best way of optimising performance.

In fact, the knowledge of how/why an LP12 is correctly put together, should encourage sensible individuals to leave the fine details of setup to their dealer. I say this from experience of reading about, e.g. 3 angle valve seat cutting: no way I have time to learn, tools, or experience to do this myself *properly* on an engine head: so it goes to the machine shop, and I pay the going rate.

So while I want to know (cos I'm interested) how it's properly done, I have no intention of playing with MY deck...
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2011-02-06, 21:41 (This post was last modified: 2011-02-06 21:43 by sonddek.)
Post: #7
RE: Setting up your LP12 - a brief overview.
Peter, thank you very much for your remarkably open-minded attitude. I really hope that Linn give you the go ahead on continuing this thread, even though I'm more likely to visit you or Derek with my deck if I return to using it. I just think it helps people who are far from dealers, or who buy something on the second hand market which has minor set-up problems. A thriving second-hand market is good for a product, especially if second-hand items perform well, as it encourages others to opt for the new product. Above all, I think some players in the market have come to deliberately mystify the engineering and science behind the products, and the products themselves, which is unhealthy. Glasnost helps good companies stay ahead of the charlatans, and serves the consumer, who ultimately only continues to pay the bills if she gains value for her money. Publishing comprehensive set-up information increases the used value of all Sondeks, and therefore the value of new Sondeks too.
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2011-02-06, 22:28
Post: #8
RE: Setting up your LP12 - a brief overview.
(2011-02-06 18:28)Cymbiosis Wrote:  I've reported myself to HQ on the tread and if its considered ok to proceed with the overview, then I will.

Ah, over the years, I've learned that it's better to ask for forgiveness than permission...........

Wink

Keith
LP12, Hercules, Ekos, Argo i, HDX, NAC252, SC, NAP250, Aerial 5B
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2011-02-06, 23:16 (This post was last modified: 2011-02-06 23:19 by Cymbiosis.)
Post: #9
RE: Setting up your LP12 - a brief overview.
(2011-02-06 21:41)sonddek Wrote:  even though I'm more likely to visit you or Derek with my deck if I return to using it. I just think it helps people who are far from dealers,

Publishing comprehensive set-up information increases the used value of all Sondeks, and therefore the value of new Sondeks too.

Thanks sonddek.

Hopefully, owners are more likely to visit their dealers now they begin to see what's actually involved, and the value of the service provided by their dealer. Whilst those owners that cant, will at least have some valuable pointers towards set-up that are more useful than those that currently exist in Cyberspace.

Fettling LP12s since 1980
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2011-02-06, 23:28 (This post was last modified: 2014-06-11 14:36 by Cymbiosis.)
Post: #10
RE: Setting up your LP12 - a brief overview.
[Image: svrz.jpg]



So, the plinth is level and we are now ready to check that the spring bolts are hanging vertically. Sometimes this is referred to as bending the bolts straight. However, in reality, the bolts are seldom bent. What one needs to ensure is that the bolt is hanging vertically. The top-plate is relatively malleable and it is this area of the top-plate where the head of the bolt is secured by an M5 Nylock that bends/distorts and sometimes needs correcting (bending).

Why do we need to do this? Well, as otherwise there is little chance of having a quiet and pistonic bounce. There are various ways of correcting this as you might read in on-line guides, but the tool of choice has to be the specially designed T-Bar.

All Linn Turntable Specialist Retailers will use it and it allows for accurate correction of the bolt (top-plate area immediately around the bolt head) so the bolt can hang vertically.

[Image: s32l7.jpg]


How or what could cause the bolts not to hang vertically?

1) A loose nut securing the bolt to the top-plate.
2) Consequence of the works necessary in ensuring the top-plate fits rattle free into the plinth in the motor corner.
3) Poor handling, such as carrying the deck round with the platter still on and consequently all of its mass acting on the suspension, hence giving the bolts and particularly top-plate a hard time.
4) If the LP12 is packed well during transportation, only a major trauma would cause a problem here, if the deck has been set-up correctly. They should not move during car journeys for example.

Next subject to be covered will be motor installation and initial alignment.

[Image: p10807671.jpg]


KR

Peter

Fettling LP12s since 1980
Tel 01162 623754
Email - peter@cymbiosis.com
Skype - peteratcymbiosis
www.cymbiosis.com
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