Best Turntable Isolation Platform?

[Chill3]

Chill,

I was only referring to fluid damping, the springs will be capped with Delrin top and bottom and sit on rubber washers.

Vince

http://physics.ucsc.edu/~josh/6A/book/harmonic/node18.html

 

Very basic explanation of the subject

 

the Derlrin and rubber washers will have little effect on spring oscillations 

 

For TT use underdamped would be better than over damped

[Once Analog]

http://physics.ucsc.edu/~josh/6A/book/harmonic/node18.html

Very basic explanation of the subject

the Derlrin and rubber washers will have little effect on spring oscillations

For TT use underdamped would be better than over damped

Early days, let's wait and see some results, plenty of time for talk later.

Have you actually been down this road yourself, using a spring loaded platform?

Vince

[Young Skywalker]

 

 

When a mass loaded TT is decoupled it should give the feeling that it is hovering and floating freely whilst under control but without  constraint in any one direction.

 

This is precisely the situation with my high mass turntable atop the Minus K BM-1. Minus K takes a purely scientific approach to the problem and some of their clients fall into the mission critical, cost no object category (not audiophiles).

 

One must know how to properly implement the Minus K for audio use, that means centring the payload (not ideal for highly asymmetric turntables unless you don't mind it being visually off centre), getting close to the maximum rated payload if you want the lowest possible horizontal resonant frequency, and minimising the drag or coupling of any attached cables (I have mine clamped to the Minus K outer "skirt" with gentle arcs for this reason). Obviously one should not locate the drive motor on a separate shelf or platform, this should be part of the closed turntable system.

 

The Minus K will displace greatly (but settle quickly) in response to high amplitude resonances (major footfalls on a suspended floor for example) while the stylus continues to track the groove unperturbed. In the real world, the value of this product is its ultra low resonant frequency for dealing with sub 20 Hz resonances of low amplitude (at least to the human eye, not so on the stylus/goove scale). Such resonances come from heavy road traffic, tectonic plate shift, building resonance, acoustic transmission of loudspeaker bass output through the floor, etc.

 

If you don't like the fact that the truly decoupled turntable system will move around in response to external stimuli (handling the tonearm, removing the record clamp, etc) then perhaps this is not the solution for you. On the other hand, when the LP is actually playing it is in a totally serene environment free of low frequency resonances... as it should be.

 

These measures are of greatest significance only when all other fundamental elements of energy transfer and geometry are accounted for in the electromechanical system. I am referring to:

 

1. painstakingly set up overhang and alignment in accordance with the tangential curve which best suits your LP library,

2. optimised tracking force and azimuth,

3. very high mass platter with sufficient self damping,

4. tonearm with optimised geometry for low tracking error,

5. tonearm with a minimal number of low friction bearings without compromising its static or dynamic balance

6. fast energy transfer away from the cartridge into the tonearm,

7. low mechanical resistance arm wiring, minimal number of breaks in the tonearm signal wire,

8. motor with very low cogging preferably separated from the main turntable chassis

9. a drive belt which is stable over time (or better still a method with no stretch and a measured degree of slippage)

10. very quiet main bearing,

11. minimised horizontal and vertical run out of the platter/bearing combination,

12. the best compromise stylus rake angle for one's LP library, and

13. optimised static balance parameters for the tonearm for each LP played (not achieved by radically raising or lowering the tonearm bearing with respect to the stylus).

Edited November 11, 2013 by Young Skywalker

[Peter_F]

 

If you don't like the fact that the truly decoupled turntable system will move around in response to external stimuli (handling the tonearm, removing the record clamp, etc) then perhaps this is not the solution for you. On the other hand, when the LP is actually playing it is in a totally serene environment free of low frequency resonances... as it should be.

 

These measures are of greatest significance only when all other fundamental elements of energy transfer and geometry are accounting for in the electromechanical system.

 

 

 

 

 

 

 

 

 

Exactly! 

[Chill3]

Have you actually been down this road yourself, using a spring loaded platform?

Vince

 

Yep done some experimentation, best results came from squash balls, which efectivly are springs and dampers in one, or bike tubes which can easily be ajusted ( best in the situation was a tube used for a light wheelbarrow)

 

change your TT, floor or stand and it all changes !

[Newman]

Just 3 days ago a friend reported his TT was sounding odd and he found the squash balls were all completely flat and providing nothing but a layer of rubber. Put me off the idea a bit. Put him RIGHT off the idea!

 

We should look for a design that is durable, not constantly degenerating.

[Once Analog]

change your TT, floor or stand and it all changes !

Easy and not expensive!

[Willco]

I am not Linnie and not really sure here, but i would have thought that suspending a suspended TT can be detrimental to the TT due to conflicting resonances? 

 

The springs in the LP12 are designed for that application and further suspending the LP12 may be a step backwards?  I think this why the light or smaller frames racks/tables works well wit the LP12 because it complements the suspension.

 

I think with suspended TT's the manufacturers have done the R&D with the suspension and all we need to do is put it on a suitable support and leave the bloody thing alone?

 

After market mass loaded plinths are a just a different kettle of fish IME.

 

Yes indeed Flemo-it was an interesting experiment--purely from their perspective--why not I thought-like I said no lasting impressions--so left to the remnants of  my potholed journey through audiophile tweaking

 

In those days Tweek was something you corrected your typing with 

 

Willco

[Chill3]

Just 3 days ago a friend reported his TT was sounding odd and he found the squash balls were all completely flat and providing nothing but a layer of rubber. Put me off the idea a bit. Put him RIGHT off the idea!

 

We should look for a design that is durable, not constantly degenerating.

 

They are cheap to replace !

[Newman]

Even cheaper to throw away.

[Hergest]

How about cutting a squash ball in half then filling it with something like silicone that retains its pliability and let it set so the squash ball never goes flat?

[Artslap]

My two cents.

 

I just set up my Linn on a solid table, but on floorboards and was getting a lot of vibration (low-frequency I'm told) from footfalls.

 

I started designing and building a Maglev table, but realised I need more suitable Neo magnets, so off to eBay.

 

In the interim I decided to experiment with Squash Balls and platforms made of MDF.

 

Platform, with a "cup" about a twenty cent piece in size (to stop the ball rolling around) in each corner.

 

From the bottom up: Table, Platform, Squash Balls, Platform, LP12.

 

I experimented with different squash balls, and the ones that work best are the Blue Balls, or the beginner balls. Higher bounce and longer hang time apparently.

 

Anyway,

 

The system works really, really well.

 

Footfalls now have to be extreme, or really close to the set-up to have any effect on the turntable.

 

I'm going top try three platforms with two layers of squash balls and see if I can improve the system.

 

Maybe a sand-box underneath later.

 

Anyway, worth a shot for those in a similar predicament with a suspended table and floorboards.

 

CP.

[Once Analog]

My Pioneer Exclusive P3 also has oil damping as part or its triple insulation (oil-damping + spring + rubber) and it physically separated from the wood plinth. The suspension is very stiff, I assume the oil damping and rubber allows a higher spring suspension than without.

35 years later still works perfectly

see the naked shot below.

http://www.thevintageknob.org/pioneer-Exclusive_P3.html

Turntable,

More to the point, are you using a fluid damping spring system platform with your Raven? And, if not, why?

Vince

[Chill3]

How about cutting a squash ball in half then filling it with something like silicone that retains its pliability and let it set so the squash ball never goes flat?

liquids are incompressible - a squash ball full of liquid is effectively solid

[ArthurDent]

I experimented with different squash balls, and the ones that work best are the Blue Balls, or the beginner balls. Higher bounce and longer hang time apparently.

 

Blue, Red, Orange, Green, White, Yellow and Double Yellow dots are how squash balls are graded. Hardest, most bounce to softest, less bounce. Heavier TT's would need harder balls or more of them.

 

Oh, and springs need damping. Don't believe that. Remove the shock absorbers from your car and see how the ride is.

Edited November 11, 2013 by KenTripp

[Hergest]

liquids are incompressible - a squash ball full of liquid is effectively solid

True. After posting the above about half a squash ball i thought about polystyrene. When you rub a couple of bits of polystyrene tiles against each other you get masses of tiny balls of it. Half a squash ball filled up with those small polystyrene balls and then something to seal the open half,( i suppose you could just cover it with tape) would make for an interesting and very longlasting support. Might sound like rubbish but then you never know.

[Peter_F]

Just 3 days ago a friend reported his TT was sounding odd and he found the squash balls were all completely flat and providing nothing but a layer of rubber. Put me off the idea a bit. Put him RIGHT off the idea!

 

We should look for a design that is durable, not constantly degenerating.

Well that's just silly.

 

Nearly all components in any facet will have perishable items and it doesn't mean that the TT is flawed or that its a crap design. Sh*t my car had to have all the timing belts changed at 100000 km, but we begrudgingly accept that enormous cost is required to ensure that the car will continue to operate as it should!  

 

Squashballs used within the appropriate weight range could be one of the best decoupling devices for the price!  4 x balls for $21.00 like really in the big wide world of hi-fi that is nothing.  How much is a new belt for a Rega  or LP12!!  How often do the rubber grommets in any suspended TT last?   

[kana]

What a fantastic thread, thanks to the mods for giving it another lease of life. Whilst reading all the informative posts I have kept thinking of two things

Firstly, do I need to look into a solution with respect to isolation of mechanical vibrations, and if so,

How do I tell that I need to do anything at all

So without any NASA approved instruments I went about trying to determine for my set up whether mechanical vibrations are an issue

I placed 3 shot glasses 3/4 full with water ( surface tension 0.072 n/m), one on the tassie oak cabinet, one on the granite platform and one on the platter (missus the rubber mat). I put on an Aerosmith cd ( big ones, rated by me as one of the worst recorded cd's ever made) and cranked the volume the highest I ever had to the point of distortion. I then looked for any disturbance. The water in all three shot glasses remained perfectly still. No sign of any disturbance.

I repeated the same experiment with isopropyl alcohol (surface tension 0.0217 n/m) and got the same result. I then changed the shot glass on the platter and the one on the granite platform with paper cups and still the same result. Even enter sandman from Metallica made no difference.

So my conclusion is for my set up I do not need to do anything, but this might not apply to everyone else.

Set up

Hardwood floorboards are floating on an underlay which sits on a concrete slab

Tassie oak cabinet stands on floorboards via 4 feet ( with carpet slide between leg and floor)

Granite platform sits on cabinet vis 4 rubber pads

Turntable sits on granite platform via three feet, the once analog tt is quite heavy and in my opinion world class in its construction.

So each piece is making contact with the least surface area and together forms a system that deals with any mechanical vibrations. The speakers are approx 2 metres from the centre of the tt.

Obviously, each setup will have its own variables that need to be addressed but this very simple test might give you some insight into how big if at all mechanical vibration is impacting your system

I am not big on the spring solution but am keeping a very open mind, so looking forward to reading about potential designs, tests etc

I did forget to mention that I conducted the test using snake oil as well ..................... Joke guys, some are taking things way too seriously and in some cases personal, we can all learn something

Cheers

Gl

[andyr]

How about cutting a squash ball in half then filling it with something like silicone that retains its pliability and let it set so the squash ball never goes flat?

 

What an unbelievably stupid idea!

 

A squash "ball" is filled with air; once you cut it in half ... the air disappears!

 

A good isolation platform is a heavy slab with some "springs" underneath - these "springs" can be "real springs" or an air bladder.  Squash balls - or a semi-inflated kid's-bike inner tyre - provide the air.

 

If some squash balls went flat, I suggest they were either old and degraded ... or they had too much weight pressing on them; 3-5kgs per ball is the ideal, AIUI.

 

 

Regards,

 

Andy

Edited November 11, 2013 by andyr

[Chill3]

What a fantastic thread, thanks to the mods for giving it another lease of life. Whilst reading all the informative posts I have kept thinking of two things

Firstly, do I need to look into a solution with respect to isolation of mechanical vibrations, and if so,

How do I tell that I need to do anything at all

So without any NASA approved instruments I went about trying to determine for my set up whether mechanical vibrations are an issue

I placed 3 shot glasses 3/4 full with water ( surface tension 0.072 n/m), one on the tassie oak cabinet, one on the granite platform and one on the platter (missus the rubber mat). I put on an Aerosmith cd ( big ones, rated by me as one of the worst recorded cd's ever made) and cranked the volume the highest I ever had to the point of distortion. I then looked for any disturbance. The water in all three shot glasses remained perfectly still. No sign of any disturbance.

I repeated the same experiment with isopropyl alcohol (surface tension 0.0217 n/m) and got the same result. I then changed the shot glass on the platter and the one on the granite platform with paper cups and still the same result. Even enter sandman from Metallica made no difference.

So my conclusion is for my set up I do not need to do anything, but this might not apply to everyone else.

Set up

Hardwood floorboards are floating on an underlay which sits on a concrete slab

Tassie oak cabinet stands on floorboards via 4 feet ( with carpet slide between leg and floor)

Granite platform sits on cabinet vis 4 rubber pads

Turntable sits on granite platform via three feet, the once analog tt is quite heavy and in my opinion world class in its construction.

So each piece is making contact with the least surface area and together forms a system that deals with any mechanical vibrations. The speakers are approx 2 metres from the centre of the tt.

Obviously, each setup will have its own variables that need to be addressed but this very simple test might give you some insight into how big if at all mechanical vibration is impacting your system

I am not big on the spring solution but am keeping a very open mind, so looking forward to reading about potential designs, tests etc

I did forget to mention that I conducted the test using snake oil as well ..................... Joke guys, some are taking things way too seriously and in some cases personal, we can all learn something

Cheers

Gl

image.jpgimage.jpg

Very good

But what were you expecting to see in the shot glass, it's not like the T. rex in jurasic park, only very specific and low and high amplitude would be visible

A phono cartridge is sensitive to a level perhaps 10,000 times of that that would excite the surface of a shot glass to visable

[Newman]

So my conclusion is for my set up I do not need to do anything, 

 

Hi Kana, you did a nice experiment and report there, thanks. However I think you can only claim that you "do not need to do anything" in relation to large amplitude vibration caused by playing loud music. Several other contributors to this thread seem to be thinking that the major causes of vibration that they want to isolate the turntable from are caused by other sources such as dancers in the room, traffic passing by, etc.

 

An alternative experiment would be to rest the stylus on a motionless LP and feed the output from your preamplifier into a computer, while playing very loud music from another deck or another source altogether, and also a separate test with the group dancing merrily on the floor boards, that sort of thing. Then take the digital file that you have recorded and play it back, or analyse it using spectral analysis software.

[kana]

Very good

But what were you expecting to see in the shot glass, it's not like the T. rex in jurasic park, only very specific and low and high amplitude would be visible

A phono cartridge is sensitive to a level perhaps 10,000 times of that that would excite the surface of a shot glass to visable

I get how sensitive a cartridge is but my line of thinking was that if i got no disturbance in the liquid at the extremes then everything else would not be material / significant at normal listening volumes. I do not have issues with springy floors, heavy traffic etc.

Just my opinion

[kana]

Hi Kana, you did a nice experiment and report there, thanks. However I think you can only claim that you "do not need to do anything" in relation to large amplitude vibration caused by playing loud music. Several other contributors to this thread seem to be thinking that the major causes of vibration that they want to isolate the turntable from are caused by other sources such as dancers in the room, traffic passing by, etc.

 

An alternative experiment would be to rest the stylus on a motionless LP and feed the output from your preamplifier into a computer, while playing very loud music from another deck or another source altogether, and also a separate test with the group dancing merrily on the floor boards, that sort of thing. Then take the digital file that you have recorded and play it back, or analyse it using spectral analysis software.

Helloooo Neumann

Sorry mate could not resist.

In my situation vibrations would be more prevalent from low frequencies from the speakers than people walking around, traffic etc.

I do like your idea of an alternative experiment, is this something that you have tried and if so, what results did you get.

Cheers

Gk

[samman]

Helloooo Neumann

Sorry mate could not resist.

In my situation vibrations would be more prevalent from low frequencies from the speakers than people walking around, traffic etc.

I do like your idea of an alternative experiment, is this something that you have tried and if so, what results did you get.

Cheers

Gk

 

Hi Kana..

 

dancing by groups of people seems to be the problem...

 

time for you the Mrs and a few friends to start performing a River dance or two , maybe even the Zorba..... :nana

[kana]

Hi Kana..

 

dancing by groups of people seems to be the problem...

 

time for you the Mrs and a few friends to start performing a River dance or two , maybe even the Zorba..... :nana

Hahaha hilarious Samman,

The system is in the pool room and there is always commotion in there ( not Greek dancing though), and have not yet managed to get that stylus to skip. I will try and get the scot next door to do some river dancing, if I can keep him away from the single malts.

How about you get the family in the m3 that is only averaging 40km per hr and get some real air into those cylinders up the Hume. Then we can do the zorba.

Cheers

Gk