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Turntable and Rack vibration control

Hi,
I moved from a Nouvelle Platine Verdier to a Loricraft Garrard 301. The big change with this move was that the Verdier comes with a terrific implementation of pneumatic suspension feet which kept the TT almost floating and hence great isolation from vibration. The result was always a noise/grain free playback and super clean backgrounds. With the Garrard, the plinth is typical custom made stacked birch ply with standard steel cones as footers. When placed directly on the rack the background is noisy, the images muddle up and overall music is not well sorted.

I do not expect the Garrard to be as quiet as the Verdier but I know it should not be this noisy either. In fact the Verdier also sounded noisy when I placed it directly on cones bypassing the pneumatic suspension feet. 

I use a Hutter Racktime rack which is not like an overbuilt audiophile rack. It is more like an open frame rack with lightweight supports. It is a bit like a Rega TT, not very damped or controlled. The rack has pointy steel feet which rests on brass spike plates (mine is an wooden floor). I guess this implementation is not sophisticated enough to keep away vibrations and let the TT play quietly. 

I am looking at two levels of solutions:
1. Replace the existing steel feet and brass plate with a quality vibration control footer below the rack
2. Replace the stock steel cone below the TT plinth with a better footer/platform.

I have tried Sorbothane, Squash balls kind of tweaks, while they reduce noise they slow down the music too.
I have also tried Stillpoints and Finite Elemente footers under the rack. They make the sound thin and metallic IMO. Platforms like Minus-K are too expensive so I have not considered them yet.

I am looking suggestions here, probably footers and vibration control devices that are more musically oriented yet well engineered like Shun Mook, Harmonix, SSC or something like an HRS platform ?
pani

Showing 6 responses by atmasphere

atmasphere's avatar
atmasphere
11,574 posts
 
There are several reasons why some or most of these vibration apps won’t work for seismic vibrations, including but not (rpt not) limited to the fact that speakers do not (rpt not) produce any mechanical feedback below say 25 or 30 Hz.

This statement is false.
atmasphere's avatar
atmasphere
11,574 posts
 
Till now I have tried to keep things simple with my garrard by using a good multi-layer birch ply plinth and using some cones to rest it on the rack. But it is now getting painfully clear that this is not a very well-sorted system. The noise floor is high, the images are grainy, the air and tranquility is missing. When I tried some softer footers, it did wonders to the sound by bringing back the air and lowering the noise floor, just that it was again not a full proof solution.
This suggests that the plinth thus created was not dead- and may have been imparting vibration coming from the stand. I say this because the soft footers helped, which suggests that they are isolating from the vibration source.

This is why a massive platform is helpful- it can be isolated from the stand if need be by the squishies and then the 'table hard-coupled to the platform. But that only works if the platform really can sink the air-borne vibration away from the 'table.
atmasphere's avatar
atmasphere
11,574 posts
 
If you plan to use a slab of granite or hardwood, the problem you are up against is that the material does have a resonant signature even if 6 inches thick. This is why the platforms I have are composed of a sandwich that also employs a steel part. That makes the structure very stable (much harder to shatter) and the steel robs energy from the other materials as they do from it, creating an anti-resonant structure. Add to that the constrained damping layer (material available from EAR, a well-known damping materials supplier) and then you have a much more neutral damping mechanism.
atmasphere's avatar
atmasphere
11,574 posts
 
@dlcockrum  don't feel too bad, the UltraResolution Technology platforms were not cheap when they were in production...
atmasphere's avatar
atmasphere
11,574 posts
 
Any tips on/sources for material and construction techniques of your TT platform that you will share? I use a similar Sound Anchors stand coupled to a concrete slab with cones.
Sadly the platforms are no longer made (UltraResolution Technology); the marble is a special grade as is the steel alloy. The marble is Italian and an inch and a half thick, with 3/4" of constrained damping material (used in submarines and the like to silence the hull) and then 1/2" plate steel on the bottom. The three layers are held together by a special glue, applied under pressure to prevent air being trapped in the sandwich.
are you on concrete below the rack or the flooring?
No- its hardwood, in a house that is over 100 years old.

atmasphere's avatar
atmasphere
11,574 posts
 
My 'table sits upon a platform that is a sandwich of marble, military constrained damping and steel. Its pretty dead.

That in turn sits on a custom Sound Anchors stand that is sand-filled. The stand is built to accommodate not only the platform and turntable, but also an identical platform on which my preamp resides. The stand has 3 additional shelves for other gear.

The stand in turn rests on a set of Aurios Pro bearings, which relieve side to side motion and vibration. Prior to this footfalls were a problem; the bearings solved that.

At this point I can play the system as loud as I want and there is no hint of strain at any level up to about 112 db (measured) at which point my amps are clipping. That's pretty loud! -yet the system remains relaxed, (apparently) at any volume. Its worth a lot to insure that the front end of the system is not subject to vibration!
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