Hi Gary,
Very interesting improvements and co-incidentally.......I have been testing and analysing the 'weakness' with the nude Victor as well.
As you have discovered.....the thin perforated metal circular surround is, I fear, the Achilles heel to supporting the Victors on spikes?
With the Technics SP10 models (as Chris has shown)..... it is possible (and preferable) to fit custom long tube spikes to the underside of the platter surround itself whereas it is exceedingly difficult to do with the Victors?
The problem is structure-borne feedback as is mostly the case with turntables?
Every supporting shelf is under 'stress' to some degree depending on its material, thickness and load, but most importantly.......on the 'span' and 'type' of span.
In my case with the wall-mounted shelf.........the cantilevered nature plus the heavy load and wood core structure sets up a particularly 'nasty' stress pattern.
What I have recently discovered is that 'stress' in any material....... creates a subsonic 'sound-field' within that material which is directly related to the 'level' of stress.
I previously thought.....wrongly I must admit.....that lower frequencies could not 'bridge' the pointy end of a spike support?
It is now known that they can and that spikes in fact 'couple' rather than 'de-couple'.
The 'stress-induced' sound waves in my cantilevered shelf are being transferred to the thin metal surround of the Victor which in turn passes them on the platter surround, motor and spindle support which the stylus then 'reads'?
This can be verified by placing the stylus on a record without turning on the motor......and then turning up the volume of the preamp until one can induce a loud low-frequency feedback loop through the speakers.
You, Gary.....have tackled the problem at the resultant culprit.....the metal surround which can work well.
I am going to attempt to tackle the problem at the 'source' by trying to prevent the transfer of this 'sound field' between shelf and turntable by isolation devices.
I'll keep you posted......:^)