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  3. 149380-2199

Dumped the rack

So I have a steel spiked Sound Organization table about 2 feet tall. On it rests a 3" maple butcher block. On that rests my slate Garrard 401 with slate feet and aluminum cones.
I had a piece of granite made and installed it on the maple beneath the turntable. Man, that sounded bad. Silvery colored and dull. I reversed the layer order and put the granite below the maple. That sounded a lot better. But not as good as when there was no granite. So I took it back out. Okay back to how it was. But something was missing. The granite did bring a feeling of stability to the image. What to do? I took the whole rack thing out of the equation and put the 401 on the concrete floor along with the preamp. This sounded best notwithstanding the wooden tone lost by removal of the maple. But the best thing, and I’m aware of the effect from reading but never tried it, was that imaging has improved by quite a margin. Like removing a veil of something. Like when someone moves their head out of your face at a concert. Now, I have to bend down to play records. 
noromance
slaw's avatar
slaw
23,973 posts
 
Or...you can have a base platform that receives the springs, have it's own leveling feet.
geoffkait's avatar
geoffkait
23,365 posts
 
But in that case the system would behave non-uniformly due to unequal loads on the springs. Ideally, when you push the top plate up and down you want to see smooth vertical up and down motion. With unequal loading on the springs the motion up and down cannot be smooth, it will be wobbly, diminishing isolation effectiveness.
noromance's avatar
noromance OP
10,208 posts
 
Update. I couldn’t handle the floor. So I stood four concrete 16×8×4" blocks on their short end. Drilled 4 holes on the 3" maple butcher block. Screwed in 4 brass domehead bolts. Rested maple on blocks -boltheads down. Adjusted bolts so it was level. Installed slate 401 on top of this. Solid and stable.
jkuc
183 posts
 

I have removed my rack. All sits on the floor on platforms.

Bare spring is not the best idea. You need to kill spring swings like Townshend does with applied rubber. The spring itself is a piece of metal and while it will isolate from seismic vibrations it will transmit micro vibrations through.
geoffkait's avatar
geoffkait
23,365 posts
 
Actually, damping or constraining springs in any manner is a bad idea. People have suggested everything from silk fabric to an oil bath to rubber. The best sound is without any damping. If you’re worried that springs ring when you strike them with a small hammer don’t strike them with a hammer when music is playing. 😬 Plus the springs under load are constrained from ringing, like using your fingers to stop a tuning fork from ringing.

 Any issues your component might have with high frequency vibration will be affected by mechanical acoustic waves as well as transformers, CD transport mechanism noise, etc. That’s why I oft say a complete plan of isolation and resonance control is required. But the primary problem is the very low frequencies, not the high frequencies, the ones lower than the lowest frequencies the speakers can produce. Any residual vibration on the top plate of the isolating device can be dealt with easily by careful application of damping. Finally, the spring itself does not isolate vibration, it’s the combination of mass and spring that forms the mechanical low pass filter of the isolator.
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