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andyr

'SkeletaLinn' v2 ...

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One pulley could have top and bottom belts, the other take the middle two....

 

Indeed, Newman.  The only problem - which I won't know is a problem until I try the setup - is ... whether the pulley height required to handle 4 grooves fits under the LP12 outer platter. :)  (I know 3 grooves fits OK!)

 

 

Regards,

 

Andy

Edited by andyr

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OK got it now.

 

How will you suppress the extra EMF if you are using AC motors so close together??

 

ATBTase. 

 

Are you suggesting the EMF from one AC motor disrupts the smooth running of the 2nd AC motor if they are "close together", Tase?

 

Or are you saying that double the EMF field strength from having 2 motors will cause problems for the cartridge?

 

My answer to both the above is ... I don't know (until I do the experiment)! ;)  I certainly cannot pick up any "EMF problem" with 1 motor ... if it does become apparent with 2 then I would think something like a mu-metal shroud around each motor would fix the problem.

 

 

Regards,

 

Andy

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Both Andy...

 

However as you say your not going to find out until the excessive is complete...

 

Good luck..

 

ATBTase. 

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Two AC motors? For shame. Your should have AC-DC.

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Two AC motors? For shame. Your should have AC-DC.

 

Haha - good one, tal.

 

 

Andy

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Wow that's cool :blink:

Never seen anything like it.

I too used to wonder what your avatar was.....

Thougt it was a half finished easel or something.

:unsure:

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I too used to wonder what your avatar was.....

Thougt it was a half finished easel or something.

:unsure:

 

 

 

Sorry Andy but..... :lol:  :lol:

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half finished

 or simply a work in progress?  And is there a distinction between the two?

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Sorry Andy but..... :lol:  :lol:

 

Yes, shows what a crap avatar it is! :lol:  I really should take a much better photo and use that!

 

So, how's the Univector/Keel LP12 sounding?

 

Since your earlier post, I've been musing about the effect of 2 motors on my SkeletaLinn (Note: I can't do this without Steve's speed controller, as you need to be able to adjust the relative phase of the 2 motors - so that the result is an even rotational force, not 2 motors working in a pulse together ... and then both slacking off for a pulse.)  Sure, it's possible that the only position feasible for the 2nd motor may cause interference to my cartridge - but I'm thinking not, given that the internals of the motor (which produce the EMI) are surrounded with an earthed metal case.

 

So it's worth a gamble - even a $450 one (1 motor + 1 motor pod + 1 motor plate)! :D  The significant improvement in sound that we heard when we increased motor torque suggests that when we double torque by having 2 motors (rather than just increasing it by 20-30% by increasing the voltage fed to 1 motor), there should be an even large improvement in SQ! :thumb:

 

The interesting thing is why should more torque improve SQ?  :confused:   Could it be that stylus drag on a belt-drive TT has a more significant effect than generally thought? :lol:

 

Andy

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Keel and Univector are performing great Andy.......but that's for another thread later on....

 

More torque on any motor is going to give better performance IMO, its when you reach the Zenith now that's the Key....

Is a 2 motor set up going to improve matters further I wouldn't have a clue.....there are pros and cons galore and without performing the exercise you will never know.

$450 seems reasonable Andy...I gabbled $7K on the Keel and Univector....no complaints at all so far.

 

You know what I'm gonna say next so I ain't gonna say it.....very radikal of me.. :P  :P

 

ATBTase.

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$450 seems reasonable Andy...I gabbled $7K on the Keel and Univector....no complaints at all so far.

 

You know what I'm gonna say next so I ain't gonna say it.....very radikal of me.. :P  :P

 

ATBTase.

 

Hehe - and you can probably guess what I'm going to say next, Tase ... 'xept I'm not! :D

 

And I don't believe you "gambled" $7K on a Keel + Univector.  You know a Keel makes an LP12 sound better - so your only gamble (which, yes, was still much more than mine) was the Univector.

 

 

Andy

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or simply a work in progress?  And is there a distinction between the two?

:lol:

Beats me, I always finish everything I st

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And I don't believe you "gambled" $7K on a Keel + Univector.  You know a Keel makes an LP12 sound better - so your only gamble (which, yes, was still much more than mine) was the Univector.

 

 

Andy

 

True Andy the Keel on a Sondek is a no brainer IMO....

 

But a Keel and Univector is ....( or was ) unknown territory so I took the gamble and fortunately they seem to like each other....a lot!! :D

 

 

ATBTase.

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Just for you, @@Tasebass, here's a pic which I have just taken of 2 silicon belts on my SkeletaLinn.  @duc's grooved pulley holds the belts very nicely 'in place' - so they don't fall down the LP12 inner platter on start-up ... and then rise, as the platter gets up to speed, like the flat belt on the Linn crowned pulley does. :thumb:

 

post-104099-0-88036000-1430214694_thumb.

 

I'm interested in input from people as to whether a stiffer belt is better - or worse - than a more elastic belt.  Which should work better for turning a platter?  There's an 'N' rating for defining stiffness/elasticity - these silicon belts shown are 'N70'; I also have bought the same sized belts in nitrile with 'N70' and 'N90' ratings - so I may be able to get N90 silicon belts as well (if stiffer is better).

 

 

Regards,

 

Andy

Edited by andyr

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As far as I am aware , the belt is supposed to decouple the motor from the platter, so based on that , greater compliance , fewer belts should be better ,all other things being equal.

Also , again as I understand it, low torque after start-up, is desirable with a standard Lp12

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Also , again as I understand it, low torque after start-up, is desirable with a standard Lp12

 There's the Hub..........Andy's deck isn't!!!

 

Interesting though......only way to find out whether the excessive will be successful is to carry on...... ;) 

 

I am with Gordon though the thinner the belt the better....and a very well toleranced Cirkus bearing assembly!!!  

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As far as I am aware , the belt is supposed to decouple the motor from the platter, so based on that , greater compliance , fewer belts should be better ,all other things being equal.

 

Aah, OK, Gordon ... so greater compliance is better - which I think means the more elastic the belt, the better.  So N70 should be better than N90.

 

But re. "fewer belts the better" ... I think this is a 'Scylla & Charybdis' thing:

  • more belts means less decoupling.  Which is bad!
  • but my gut feel says that the amount of torque applied to the Linn sub-platter is probably more with 2 belts than it is with 1?

So it's a trade-off. ;)

 

But in my next SkeletaLinn scenario - with 2 motors - maybe 1 belt per motor is the best arrangement (rather than 2)? :)

 

Also , again as I understand it, low torque after start-up, is desirable with a standard LP12

 

Yes, that is what the Lingo does:

  • Low torque results from reducing the motor voltage to ~80v
  • Reducing the motor voltage to ~80v means less motor vibration - which is good
  • This appears to be important for an LP12
  • However, the experiments I did with several people last year showed that increasing torque - by increasing (not reducing!) the voltage to the motor - improves the sound
  • But you can only do this if you have first optimised the phase difference between the motor windings to minimise motor vibration (as Steve's speed controller can ... but the Lingo cannot). :D

So, IMO, low torque is just Linn "gospel"! :P

 

 There's the Nub..........Andy's deck isn't!!!

 

Interesting though......only way to find out whether the excessive will be successful is to carry on...... ;)

 

I am with Gordon though the thinner the belt the better....and a very well toleranced Cirkus bearing assembly!!!  

 

Both SkeletaLinn v1 (owned by @djb) & v2 (owned by me) have a Cirkus bearing.  Given that it is made by Linn ... I would have to assume that it is very well toleranced! :P

 

Re. thinner belts ... I tried 2 much thinner belts last year - 1.6mm cross-sectional diam.  Being round, they seemed not to be able to 'grip' the inner platter well ... with the result that there was excessive 'judder' on start-up.  The current belts (2.62mm in cross-sectional diam) do not have this problem - because, like a fat motor bike tyre vs. a thin one ... there is more rubber contact!

 

 

Regards,

 

Andy

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Hmmm, I'm looking forward to hearing about the WOS CS100 and how it compares to your other cartridges.

Edited by MrRogers

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Andy , don't think the low torque drive is "Linn gospel" so much as established practice in many of the UK's belt driven suspended tt's. The Gyrodeck has had  the option to run multiple belts for many years but if I remember correctly most users returned to single belt drive after experimentation.

Perhaps have a look ar Pink Triangles/Funk firms Vector Drive mod for the Lp12 and see if that can be adapted to your open frame tt.

post-131373-0-07462300-1430298581_thumb.

 

http://www.thefunkfirm.co.uk/turntable_upgrades/LP12_Upgrade.html

Edited by Ozcall

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Andy , don't think the low torque drive is "Linn gospel" so much as established practice in many of the UK's belt driven suspended tt's. The Gyrodeck has had  the option to run multiple belts for many years but if I remember correctly most users returned to single belt drive after experimentation.

Perhaps have a look ar Pink Triangles/Funk firms Vector Drive mod for the Lp12 and see if that can be adapted to your open frame tt.

attachicon.gifAnkhor.png

 

http://www.thefunkfirm.co.uk/turntable_upgrades/LP12_Upgrade.html

 

Yes, it's an interesting design, Gordon - I had discussions with Arthur K in the early 2000s about his Vector Drive.  I didn't proceed bcoz (I think) I thought mounting the motor on the subchassis was a bad idea.

 

But he has 1 motor with 3 pulleys - I will (if the experiment works out) have 2 motors with 2 pulleys. :)

 

 

Andy

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Interesting what is said about DC motors.............Andy!!! ;) .......

 

To me a belt driven deck should be....

 

A Structural assembly to cater for....

 

1 motor and pulley

1 belt 

1 bearing

1 platter

1 Tonearm

1 Cartridge.

 

I understand that the execution can be endless but the principle must remain the same IMO....

 

 

ATBTase.

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Interesting what is said about DC motors.............Andy!!! ;) .......

 

To me a belt driven deck should be....

 

A Structural assembly to cater for....

 

1 motor and pulley

1 belt 

1 bearing

1 platter

1 Tonearm

1 Cartridge.

 

I understand that the execution can be endless but the principle must remain the same IMO....

 

 

ATBTase.

 

Tase, Tase, Tase ... you seem to have drunk deep of Ivor's "Kool Aid"!  :P 

 

Many decks allow you to use 2 arms.  So mine is just one of them.

 

Some decks have multiple motors - but the LP12 cannot accommodate this.  Whereas:

a. my SkeletaLinn can be set up with 2 motors, plus

b. the motor speed controller allows a 2-motor setup to be optimised (unlike a Radikal or a Lingo).

 

I can see we are going to have to meet, to compare:

*  your Keeled/pimped-plinth LP12 with 9" Univector and Radikal

* against my 2-motor SkeletaLinn with 12" Univector and Number9 speed controller. :D

 

Regards,

 

Andy

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So are you gonna change that avatar.......?

:lol:

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So are you gonna change that avatar.......?

:lol:

 

Yeah, yeah ... one of these days (weeks?)!! :lol:

 

Andy

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