October 6, 2010

Restoring An Icon. A Pictorial Guide to Re-Building A Linn Sondek LP12.

This project has been a long time coming, due to un-foreseen circumstance, it took a whole lot longer and turned out to be more work than I had bargained for!

First up, stripping the Linn Sondek LP12 down was the easiest and fastest part of the project. All I had to make sure that I broke, and lost no parts. Upon dismantling, I had all the old parts stored in a marked box. We shall continue from the point we had left off, the plinth!

Where we last left, the wooden plinth of the Linn LP12 striped bare, and and masked, ready for re-finishing of lacquer.

The wooden frame plinth took the longest time to do for one reason, finding the right carpenter for the job! The job it self seemed easy enough, all one had to do was to strip down the old top coat lacquer, give the wooden plinth some fine sanding down, then re-apply the top coat lacquer of similar colour and quality. However, the first carpenter I took the plinth to was not sure if he was up to it, but since he had been making furniture for some 5 star hotels in Kuala Lumpur, I confidently convinced him that he was more than qualified. Boy, was I wrong! It turned out that the Linn LP12 plinth surfacing works takes a sifu of the absolute highest carpentry finishing skill level to complete. I then consulted my good buddy Felix, who happens to know some of the best guys in the business, "I'll take care of it, but please don't rush me" he says. I left the plinth with Felix, and it was nearly another 2 months before he called and said "it's ready, I think you'll be pleased with the results", and when I first saw the plinth, it looked just like brand spanking new!Some say changing the lacquer changes the sound of the Linn LP12, I can't be sure about that as too many things were changed in the course of rebuild.


The completely re-finished plinth, back from the carpenter's. JT is seen here giving the plinth a final pre-assembly buff, to clean out masking lines and surface dirt accumulated on the new lacquer finish.

Then with the help of another buddy, who does not want to be named, so let's just call him JT(Justin Timberlake???), shall we. We start the rebuilding work of the LP12 turn table. JT has been an LP12 turn table enthusiast since the late 70's. He has more than 30 years of experience setting up Linn turn tables. Because he does so(well, used to) much work with them over the years, he has accumulated all the necessary tools for the job, like the Linn set up jig, Linn protractor and strobo light set, and the Linn tool kit set which includes a highly accurate spirit level. While all these are not absolutely necessary, they do make the job much more convenient and safer.
The wooden plinth mounted on the Linn set up jig, ready for re-assembly.

With all the masking tapes removed, the wooden frame plinth was given a final wax buff before it was clamped on to the Linn set up jig. The use of the jig made it easy to maneuver and allows access from all angles to the turntable as one assembles it.
The other tools required for the assembly. A Linn tool kit set, strobo light and spirit level.

JT then proceeds to place the stainless steel top plate, and secures it to the wooden frame plinth via 2 long screws. The top plate also houses the motor and pulley of the turn table.
JT scratching around the earthing point screw holes on the sub chassis to ensure clean contact.

Next, JT focuses on the old style steel sub chassis(as typically found on all pre Cirkus LP12s). All the screw holes for ground wire mounting points are given a scratch in the surrounds to ensure clean contacts later.
The parts for the sub chassis assembly, rubber grommet, springs and washer(not shown).

Because the original springs have became soft and rubber grommets hardened, they had to be replaced. JT tells me that worn springs and hardened rubber grommets supporting the whole sub chassis assembly, and thus the turn table will not allow the LP12 to perform to it's full potential. "The whole idea of the Linn LP12 turn table is to get the bounce right!" he said, a remark which will be repeated thru out the course of assembly. The whole sub chassis and platter which rest on the 3 springs and rubber grommet must be set up to bounce evenly, in a non jiggly manner, for only two or three times, that is the "right kinda bounce". The newer and latest batches of springs(which are firmer) and rubber grommet holds it's setting better than the older versions from the 80's(Remember, that my Linn LP12 was manufactured in 1984).
The talcum powder bath for the rubber grommets.

Before installing the rubber grommets, JT puts them in a talcum powder bath. Again, this has nothing to do with the sound, but more for longevity and easier to turn them in to position during final set up procedures. If one does not know better, all this preparatory work would not have even come to mind.
The slotted rubber grommet in to the sub chassis.

Like the rubber grommets, the slots on the sub chassis where they are mounted are given the talcum powder treatment, again for easier adjust ability during the final setup. Once the rubber grommet are sitting perfectly in their slots, its time to fit the springs over them.
The view from the under side of the sub chassis.

This is the washer to allow the adjust able nut(not shown) to press down on the spring/rubber grommet assembly.

The springs are then topped by another piece of rubber grommet and steel washer. An adjust able nut is later screwed in for final adjustment to set up "the bounce" remember that?
The Linn Valhalla power supply board, mounted on a steel bridge.

Once all the three spring and rubber grommet assemblies is complete, JT moves to the Valhalla power supply board. This board sit on a steel bridge via 4 plastic clips, when attached to the bottom of the 2 long screws holding the top plate, acts like a bracing to provide strength to the wooden plinth.
The earth wire routing is carefully considered, to ensure that it does not impede or effect the turn table's bounce.

The power supply board's earth wire is secured to the sub chassis(remember as JT had earlier scratched the screw holes for clean contacts). Again, care must be taken to ensure the wire dressing does not impede or effect "the bounce" in any way!
The motor wires are then attached to the Valhalla power supply board.

The mains wire routing. Note the ferrite tweak, a personal favourite of mine.

This is followed by mains wire with earth. Again, do keep in mind that when the routing the wire dressing so that it doesn't impede or effect "the bounce" factor. Note that I have included a little ferrite clamp tweak to the mains wire. In past experience, this easy tweak helps to reduce motors noise and vibration by a small extent, which is worth while.
My old arm board had de-laminated in to 3 layers due to age, as compared to the new replacement.

JT buffing the Linn Ittok LVII tone arm collar.

The final assembled arm board, ready for mounting on to the sub chassis.

The tone arm collar and holder is them mounted on to the arm board. The whole assembly is then fixed on to the sub chassis, using three very short screws. These screws, slotted in via the sub chassis, just barely bite the arm board enough for hold. Please ensure not over tightened the screws, which will result in lost of bite due to damaged thread on the arm board side. Finger tight is good!
The arm board mounting, viewed from the under side.

The arm board viewed from top, should be squared evenly on all four sides.

JT testing out the slack required for the SME style tone arm cable connector, to ensure it doesn't impede, or effect the bounce factor.

The Linn Ittok LVII tone arm is then inserted in to it's collar for final assembly and setting up. When attaching the tone arm cable dressing, it is again important to take care of "the bounce" factor. This is where the importance of the P-clip(the whitish plastic clip on the left) holding the tone arm cable is very, very important. A worn or deformed P-clip will not properly hold the tone arm cable in place. Before locking the nut of the P-clip, do ensure to allow a little slack(not too much) to the tone arm cable dressing, to ensure again, it does not impede or effect "the bounce". All one has to do once inserting the SME style tone arm cable head in to the tone arm, is to press the springs down to the maximum, ensuring to have just enough cable slack to allow "the bounce".
The Linn protractor in use.

The sub platter and top stainless steel platter is then temporary placed in to the bearing slot mounted on the top plate. This is to facilitate the next step, which is the cartridge set up and alignment. A Linn protractor is placed on top of the platter to allow accurate cartridge mounting and alignment. The cartridge, which is a Clearaudio Stradivari, is mounted on to the tone arm head shell, with 2 screws.

The Linn protractor allows the mounted cartridge to be checked in 3 points. The center point is first referenced, then the second and third points, which forms an arc on the outside and inside of the platter is used to confirm the correct mounting position. This procedure is repeated until all three points that form the arc is in line with the cartridge. JT mentions that in his experience, the best place to start mounting the cartridge is to first reference the point of the stylus tip to the pointy tip in the center front of the head shell shape when viewed from the top.
JT advices that it's a good habit to completely remove the tone arm from the turn table, when mounting the cartridge.

Despite his years of experience, JT still needed to re mount the cartridge and go through the mounting calibration three times before getting it right. JT has another tip too. He advises to detach the whole tone arm from the collar, when mounting the cartridge. Should one chooses not to do so, will end up stressing the tone arm bearings, and in the worst case, can result in bearing jam, or damaged tone arm. "It's a lot more work, but it's a lot less risky too!" he remarked.
The final cartridge alignment process.

With the cartridge mounting calibration points taken care off, it's time to move on to the cartridge alignment it self. Based on the little square grids printed on the protractor, as pictured above, one has to make sure the cartridge body is aligned straight on both sides of the grid lines.
JT checking out the VTA visually. Boy, do I admire his shinny crown of glory! He!He!

Setting the tone arm holder rest height.

Next is to adjust the VTA of the tone arm, by visual means. The tone arm should technically be leveled straight during play when viewed from the side level angle. A bit about adjusting VTA, which we'll use the back end, where the counter weight resides as a guide. A lower in the back end VTA setting will usually reward with a tonally richer sound. A higher in the back end setting usually yields a slight more focused and forward sound. A used and un worthy LP should be used for this test. Then the tone arm holder is set for the correct height, so that the arm swings in to place smoothly as pictured above.
A visual cue as to the optimum belt alignment with motor pulley.

Lastly it's time to set up the rubber belt and adjust the motor pulley. There is two tiny screws on the top plate next to the motor and pulley. Using this two screws, one can tilt the motor pulley to effect belt tension. The right belt tension means the belt will not fall off the pulley when turning the platter. JT likes to maintain the belt in the center of the pulley height as pictured above.
The strobo speed check test.

The Linn protractor also functions as a strobo speed checker, when used with the Linn strobo light. The Linn strobo light comes with an attachment that allows it to slot in to the hinges to ensure stable readings. It's very simple to see if one's Linn is spinning accurately at 33 1/3 rpms. The Linn protractor has slots printed all around the edges and during spinning, all one has to ensure that the illusion of slots do not move more than 3 places in a minute, and it's considered within speccifications. With my old rubber belt, the slots moved exactly 3 places during the minute. While still within specs, JT recomends to changing a new belt, as the old one would not be within specs for much longer. With a new belt, the slots only moved 1 place during a minute of spinning under the strobo.
Soaking up the old tired dearing oil, in preparation for new oil during final sub platter/platter assembly.

Finally the old baering oil is taken out of the bearing well, by means of stuffiing some tissue paper in to the bearing slot. JT recomends that when I get home, I shall remove the tissue which by then, would have soaked up most of the oil inside. I should then proceed to pour 1/3 of the new oil in the bottle, packed by Linn, in to the bearing slot. Then place the sub platter in to the bearing slot, do not press! Instead, allow gravity pull and weight of the sub and main platter to push it down. This will ensure all the air trapped inside the bearing slot to escape with time, creating a perfectly sealed bearing. Once a perfect seal is achieved, it'll be very hard to pull the sub plater out of the bearing slot!
Now, the Linn Sondek LP12 is ready to play! I'll report on the sound in a later posting.


I wish to offer my unreserved thanks and gratitude to Felix and JT for their help in realising this re-build, which has taken a lot of their time and efforts. I count my blessings every day, to have friends like this two fine gentlemen.



14 comments:

Capernaum Creative Solutions Inc. said...

AWESOME! AWESOME! AWESOME! I Love it. :-)

Big E said...

Thanks buddy,

I couldn't have done it without your help.

Capernaum Creative Solutions Inc. said...

I am just glad to be a part of yr TT "refurbishment". It is pretty awesome to see the detail and precise work gone into yr LP12 by "Justin Timberlake". I am pretty impressed. Excellent write up. I learnt somethings.

Pug said...

You arm board, is the replacement a new one from Linn. How much did you pay for it ?

Pug said...

Your new arm board, is it new from Linn or did you have it done locally ?

How much is it ?

Big E said...

Pug,

JT had have many Linn LP12 parts, including a few spare new Linn arm boards lying around so, this project is really not quite possible without his help.

I am not sure what the price is locally with the current local Linn dealer called Perfect Hifi, but I can check with them.

kiarch said...

Congratulations!! I am sure after a proper restoration, you will understand general conception of LP12 is a TT needing constant setting-up is not true; when it is done properly by this expert call Justin, it will gives you years of good vinyl music.

I speak on experience because my LP12 was done by the same JT, it is still singing song.

HS said...

Big E,
A ferrite core installed at the power cord of a high end analogue turntable? What is the difference in audio quality with and without?

Big E said...

HS,

In regards to the ferite tweak in an ol' turn table's power cord, from past experience, it's benifit is subtle at best. It tends to reduce noise floor just a bit. Images can float out a bit better from the back ground perhaps.

As I said, in the context of the Linn rebuild, I can't be sure which part of the sonic improvement did the ferite bring to the overall result. As I said, in the process of the rebuild, too many things were changed at once!

But do try it, and see/hear for your self. You may or may not like the result? YMMV certainly applies here.

Big E said...

Jo,

I was in part motivated by your pristine condition LP12! Thanks for the kind words.

That JT is some kinda wonderful! Isn't he?

kiarch said...

Hi Big E,

Oh yes, you are right, this Justin Tanboleh is indeed wonderful person to know. His knowledge on LP12 is one of the best in this region.

He is most kind to has helped you and me.

Again, many congratulations!

HS said...

Big E,
Ooops! My apology. I saw the picture but missed your comment on the ferrite core. I thought ferrite core is meant for digital device with poor filtering.

Theo de Jager said...

great write up, thank you.
I just dusted of a 1970s LP12. is there a way I can become friends with jt?

rkay5 said...

Hello,
You should never never use talcum powder on the rubber grommets of a LP12 as it can make LP12 suspension going out of tune .Talcum power does make set up easier but it should not be used just to make set up easier just ask the men who do Linn LP12 set up for a living....