Nude Turntable Project

Richardkrebs,

Is there a secondary issue here?Could there be acoustic feedback following the initial EMR problem?

I think you're right....
When I play music at loud volume containing 30-60Hz bass drum beats (like Cream's 2005 Royal Albert Hall Concert or Copland's 'Fanfare for the Common Man' Ref. Recordings)....this 50/60Hz feedback loop can take hold.
At the same time I can feel the vibrations in the supporting shelf and in the granite cradle...😱
As the shelf is directly over the Vandersteen subwoofers, this seems like air-borne sound converting into structure-born feedback.
But why only recently...and why is the Raven not similarly affected as it is identically situated?

Halcro
Have you tried testing the resonance characteristics of the granite pipe?
The material does have a tendancy to ring like a bell.

Also by "identically situated" do you mean that you placed the Raven at the same place on the shelf as previously occupied by the Victor?

Does the Raven have a suspension?

Hi Richard

The Raven does not have suspension. It does however have OEM Stillpoint feet

Henry,
If you will recall some years back in my experimentation I was running three tables side by side. I had each set up well on the concrete slab. Making nice music in their own different and unique way.

The test for structure feed back was to lower the needle on a still record un mute and crank the volume slowly. Then jump up and down beside each table searching out air pockets in the poured concrete. You're not a true audiophile until you have danced with your turntable.

I then brought out the bad boy. The Acutex 420 str. As naked a cartridge as there ever was. And I teamed it up with wiring that was unshielded except for its own poly covering. What followed was interesting.

The Jean Nantais Lenco exhibited a drone like noise. If I remember it was almost mechanical sounding. In talks with JN, I added an extra ground from the motor to the plate but to no avail. I was unwilling to make further mods to his table so that was the end of the road.

The Technics SP10 II made noise and required an extra ground. It was added from where the bolts goes into the casing and then into the preamp. This cleaned things up and it was quiet. Almost.

My former modded thread drive TNT/SDS drive with pneumatic suspension. An absolutely black silence, as black as the table itself. It revealed a veil in the music that the SP10 was making.

As we say - You don't know what's there, until you hear "it" removed.

So the 420str is a very good test cartridge - imo. If things pass with that cartridge they can only get better from there. Cheers

Have you tried testing the resonance characteristics of the granite pipe?

Granite pipe 8^0

When I started this  exercise over six years ago, I began rather crudely with the Victor TT-81 simply supported on cones.
MODEL 2010 
Unsatisfied with the 'flexure' of the motor-unit about the cones, three years later I designed an independent stainless steel cradle to support the now 'fully nude' TT-101 motor unit...
MODEL 2013 
Two years after that, still unsatisfied with the vibrational and torsional movement possible with the flimsy steel frame.....I designed a cradle cut from a solid block of black granite and then polished.
MODEL 2015 
Despite the fact that my floor is a reinforced concrete slab cast on the ground and the turntable is supported on a thick laminated shelf cantilevered from a solid brick wall.....I know that there are low-frequency vibrations in all building structures and materials particularly materials under stress like suspended floors, shelves and equipment stands.
When materials are in stress (particularly tensile stresses)....they actually emit low-frequency vibrations between 2-10Hz and these frequencies are easily transferred through turntable plinths, motor units, spindles, platters, tonearm mounts and thus into the tonearms, cartridges and vinyl records themselves.
So for this year....I invested in a Herzan TS-140 Active Isolation for my turntable/armpods combination.
MODEL 2017 
This stand is designed for electron microscopes and contains numerous electronic actuators which isolate to 0.5Hz in all six degrees of freedom.
HERZAN 
So what is the difference.....?
Exactly what I expected.....but still almost unbelievable 💥
The improvements at first seem subtle but are all-encompassing....
Be aware.....this has NO effect on frequency response,
But every frequency SEEMS affected by suddenly having a purity, transparency and 'body' that was somewhat 'cloudy' before the Herzan.
There is absolutely no strain or stress to any music at any volume and as you turn up the volume...so you want to continue turning it up 🎶
I thought perhaps the bass would be deeper or more solid but no.....the bass seems unaffected but all the clarity and delicacy is bestowed upon the midrange and the highs with a singular crystallinity emanating from every cymbal, string, flute and horn.
The first casualties of unwanted vibrations in the analogue domain are the tiniest molecular-sized groove modulations which contain the most ephemeral informational DNA.
Qualities like body, soundstage, spatial depth and positional indications are simply smeared when other unwanted vibrations are present.

So it's been an illuminating and rewarding journey...
I hope you all enjoyed it with me....
Am I finally done?
I think so 😎