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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
anvil_turntables's avatar
anvil_turntables
53 posts
 
Also, I'm not a fan of flywheels. They add unnecessary cost and complexity and add a second often poorly designed bearing. Much better to just add more weight to the platter. Don't get too caught up in the noise issue. Its not that hard to deal with in a GOOD all around design. I would take the 300 rpm motor because I like the larger surface area and grip that a larger pulley provides.

Hope this helps


dlcockrum's avatar
dlcockrum
2,190 posts
 
Thanks Bruce.  Very, very helpful.

Dave
geoffkait's avatar
geoffkait
23,365 posts
 
As I just posted on another thread about vibration the usual damping techniques, especially those employing soft rubbery materials, often fail to accomplish the mission. What is really needed for these stubborn cases is a method that allows the mechanical energy to exit the system rapidly, rather than stick around and reverberate inside the system. So, instead of attempting to muffle the vibration or control it with rubbery materials like Sorbothane it’s usually much more effective to employ either constrained layer damping or relatively simple devices like audio cones especially DH Cones, very hard materials, even crystals can be very effected in this regard. Or even, as suggested by the OP, Shun Mook Mpingo discs. Those devices provide a *path of least resistance," a mechanical diode, for the energy to exit stage right, as it were. 💃

dlcockrum's avatar
dlcockrum
2,190 posts
 
Received and installed 300 rpm/flywheel assembly today in place of my original 600 rpm motor. Yowza! Immediate improvement in PRAT and ebb-and-low of the music.

No need to repeat the usual superlatives, but I will say that the reduction in the noise floor, er, floored me. A layer of foundation noise that I had always blamed on my phono stage is gone. So easy to hear more deeply into the music now.

I also noticed improved coupling of the thread drive from the platter to the flywheel’s much larger spool vs directly from platter to motor spindle before. The flywheel and motor pulley continue to turn/wind down with the platter without slippage after shutting off the motor and the combo seems to even pull to speed more easily despite the added mass of the flywheel.

The added mass/density of the motor/flywheel combo makes the "tap test" futile. No transfer of pops, thunks or rumbles from finger taps/flicks to the motor/flywheel assembly on to the stylus. Even though the old motor is very solid and very heavy, it couldn’t touch the new one for damping/isolation.

A very good improvement. Now on to the Symposium Ultra platform installation...and, yes, Geoff, springs under the Big Rock. ;)

Dave
lohanimal
659 posts
 
Given the significant reduction in moving parts - I guess a well executed DD would be the best at managing vibration from a theoretical point of view.
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