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Old 11th February 2006, 07:56 AM   #1
fergs1 is offline fergs1  Australia
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Join Date: Jan 2005
Location: melbourne
Default diy morsiani antiskating questions

Greetings all, would someone kindly explain in detail the morisani magnetic antiskating regarding adjusting(I assume its the height of the magnets on the armbord that are adjusted) and what type of magnets. I assume neo's are too strong, any thoughts. Also I intend to use fairly high compliannce carts as I haven't got the dough to go down the mc road. Is this an issue?Also any photos of finished unipivots employing this system would be greatly appreciated. kind regards fergs
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Old 11th February 2006, 09:23 AM   #2
AndrewT is offline AndrewT  Scotland
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Hi,
A magnetic system may impart a twisting (azimuth) motion into the unipivot and the magnitude of the twisting could change as the arm sweeps across the playing surface.
Careful design to eliminate this effect may be needed.

Slightly off topic:-
I have read an article (& website) that shows a pair of dumbells attatched to the headshell to increase azimuth inertia. It is an ideal way to load a unipivot to help prevent lateral movements and vibrations.
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Old 14th February 2006, 11:04 PM   #3
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Location: Scandiano-Reggio Emilia-ITALY
Default Morsiani antiskating

Nobody can explain thsi better than Morsiani himself.
If you look in my website www.morsiani.it there are enough pictures and one drawing showing how the 4 alnico magnet are placed.
The antiskating force is adjusted employing an uncutted disc ,then you can employ a test disc with recorded frequencies and a dual trace oscilloscope , but this is not mandatory.
Thre are two magnets in the pivot turret,these can be called rotor ,and two magnets in the armbase,these can be called stator.
The two magnets in the turret are placed horizontally and with opposed polarity,the two magnets in the armbase are placed vertically and the north pole is in the bottom side.
Raising these magnets the force increases , because the distance between the stator and rotor is diminished.
Then the two magnets in the pivot turret are placed in a disc which can be turned, this adjusts the run of the antiskating .
The noth pole of one magnets of the rotor must be aligned with the south pole of the magnet inthe right side of the stator when the stylus is on the first groove.
My magnets dispalcement can demonstrate that the skating force is not constant across the disc,but it diminishes toward the disc centre.
Adjust the two side magnets of the stator at the same height to keep the arm stopped when it is at the middle point of the disc.
Then put the arm at the disc end,and the arm returns at the middle.
This means that from the middle to the end the antiskating force is too much.
Then put the arm at the beginning of the disc,the arm run toward the middle.This means that the antiskating force is scarce.
This can be done with an unipivot arm,because the friction is very low,some cardanic arms with balls race bearings have friction greater than the small difference of the skate force,so this effect can not be detected.

Now you can push up the magnet on the right side of the arm,increasing the force from the beginning to the middle,and pull down the magnet on the left side of the arm,diminishing the antiskating force from the middle to the end.
In this way the arm can be adjusted to stay stopped in the all of the disc surface ,but this is valid for a flat disc,but the cutted disc offers more surface to the stylus,so a gretar force is useful .
I adjust the arm to have a slow motion toward the outer of the disc.
At this point a test disc is useful for fine adjustment to have the best traking in all the disc surface.
The best traking is obtained when the pressure of the stylus is balanced on the two sides of the groove from the beginning to the end of the disc.
This can not be allowed by constant force antiskating ,my method is more accurate .I invented this 10 years ago,and since now it is unequalled ,because this reduces distortion and the vinyl wear,remember that the diamond is harder than vinyl !
Best regards,
Carlo Morsiani
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Old 15th February 2006, 12:06 AM   #4
fergs1 is offline fergs1  Australia
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well I didn;t think i'd be talking to the man himself. your explanation is clear as a bell, thankyou. what would you sugest in the way of magnets for the diy'ers (are neo rods too strong)and also is the spacing of the turret magnets critical..this system is far more appealing than taangentiaal arms in terms of ease of construction. Carlos thankyou for your help, its a brilliant desiign cheers fergs
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Old 15th February 2006, 04:18 AM   #5
fergs1 is offline fergs1  Australia
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oops! I mean Carlo cheers fergs
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Old 15th February 2006, 08:40 AM   #6
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Hi Fergs 1,
really my arm is easier to make than a tangential arm ,end easier to set-up,and it works without any problem forever ,and it sounds definitey better than tangential arm,cardanic arm,and all unipivots arm without antiskating or with wire and counterweight antiskating .
I published my arm 10 years ago,there are more DIY unit made than the units made and sold by me.
As Mr Constant Verdier wrote , it is a previlege of the best ones to be copied .
In 10 years I had enough work ,so DIY copies are not a problem,instead this is the evidence that
my metod is validated by reproducibility.
You can see that the antiskating is considered an accessory which can be deleted,instead this is very important to have good traking,and keep low the distortion.
Following my method,
You will have stable and focused stereo image,and female voice will stay firm ,and will not fly around like a butterfly .
Then remember that the bearing is the heart of the arm,the pivot matter has its own sonic signature,I choose the harmonic steel,but you can experiment what you like as diamond,sapphire,tungsten,wolframium,stell of various hardness..


Best regards,Carlo Morsiani
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Old 15th February 2006, 05:58 PM   #7
fergs1 is offline fergs1  Australia
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o nce again thankyou for your help. I'll post some photos when i'm finito
kind regard fergs
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Old 20th February 2006, 04:17 PM   #8
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Location: Denmark
A big thanks from me also for your explanation

A few more readings and I maybe can figure it out, I think I have to build it and see it in action to fully understand it. I have difficult understanding mechanical ideas without seeing/touching it.

Will a diameter of 5 mm work for the alnico magnets?
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Old 21st February 2006, 06:23 AM   #9
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In attachment two drawings,
in drawing n6 the arm turret and the magnets displacement are shown ,
in the drawing n7 the arm is shown from the top side,so you can see the alignment of the magnets at the beginning of the disc.
In action you will see how it works.
The disc with two oppsed magnets on the top side of the turret are kept in centre by a proturusion ,which diameter is of 5 mm,in this there is screwed a screw without head of mm 3,and an M 3 blind nut locks the magnets disc to the turret,losing the blind nut you can adjust the antiskating run.
I never released these drawings on internet before, there is a copyright owned by me,and these drawings can not reproduced or duplicated in other websites than www.diyaudio.com without my permission.
Best regards,Carlo Morsiani.
Attached Images
File Type: jpg cm1dis7.jpg (57.8 KB, 1017 views)
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Old 21st February 2006, 11:30 AM   #10
fergs1 is offline fergs1  Australia
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greetings Carlo, on behalf of the diy community I thankyou for your generous spirit and I for one respect your wishes.I'm curious as to what it was that sparked the immagination in the first place. What made that light bulb light up above your head.
ciao fergs
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