Dear Alec,
Having read some of the early responses I think the idea of taking an unsuspended table and converting it into a suspended one by means of the support seems to defeat the object of the exercise ;^)
I know that this suggestion might go against the grain but assuming that you are applying the vinyl directly to the copper platter, have you considered trialling a few mats?
One reason I say this is that the mech impedance of the copper platter is dissimilar to vinyl and you may get a more acceptable result by improving the match?
Speaking from experience I was in a similar position to that which you describe. It seemed like sacrilege to add to what should be a perfect interface but I cured the problem by first of all adding the basis of the Ringmat Support System i.e. a hybrid mat consisting of a thin latex Base Mat plus the "Gold spot" Ringmat.
Further to this I also notice that dressing the cables to prevent undesirable vibration being passed into the T/T was critical. (In fact it is critical to suspended tables too but possibly more so here)
The stand I use is multi-stage (3 shelves), tri-spiked on each level (so no micro-rocking) and made not from maple but oak. It isn't massively heavy and the resonant frequency isn't too low - so it will act as a mechanical filter when situated on a concrete floor.
The spikes ensure that only a tiny proportion of vibration is passed from one level to the next and this shrinks correspondingly as you progress up the stack. By the time residual vibration reaches the T/T it has passed through 5 levels of minimal coupling (if you include 2 within a set of Stillpoints.)
Whatever is left we would hope would be dealt with by the T/T's own mass.
This basically leaves airborne feedback and the Supply/Tonearm cables as the final sources of feedback.
Airborne feedback is almost untreatable apart from a separate room or moving the T/T further away from the speakers. The T/T should handle this ok provided it isn't mounted directly on top of the speaker. ;^)
Mech cable resonance on the other hand is treatable. It's worth playing around with this factor as I mentioned earlier.
Hope my experience proves helpful in some way.
Having read some of the early responses I think the idea of taking an unsuspended table and converting it into a suspended one by means of the support seems to defeat the object of the exercise ;^)
I know that this suggestion might go against the grain but assuming that you are applying the vinyl directly to the copper platter, have you considered trialling a few mats?
One reason I say this is that the mech impedance of the copper platter is dissimilar to vinyl and you may get a more acceptable result by improving the match?
Speaking from experience I was in a similar position to that which you describe. It seemed like sacrilege to add to what should be a perfect interface but I cured the problem by first of all adding the basis of the Ringmat Support System i.e. a hybrid mat consisting of a thin latex Base Mat plus the "Gold spot" Ringmat.
Further to this I also notice that dressing the cables to prevent undesirable vibration being passed into the T/T was critical. (In fact it is critical to suspended tables too but possibly more so here)
The stand I use is multi-stage (3 shelves), tri-spiked on each level (so no micro-rocking) and made not from maple but oak. It isn't massively heavy and the resonant frequency isn't too low - so it will act as a mechanical filter when situated on a concrete floor.
The spikes ensure that only a tiny proportion of vibration is passed from one level to the next and this shrinks correspondingly as you progress up the stack. By the time residual vibration reaches the T/T it has passed through 5 levels of minimal coupling (if you include 2 within a set of Stillpoints.)
Whatever is left we would hope would be dealt with by the T/T's own mass.
This basically leaves airborne feedback and the Supply/Tonearm cables as the final sources of feedback.
Airborne feedback is almost untreatable apart from a separate room or moving the T/T further away from the speakers. The T/T should handle this ok provided it isn't mounted directly on top of the speaker. ;^)
Mech cable resonance on the other hand is treatable. It's worth playing around with this factor as I mentioned earlier.
Hope my experience proves helpful in some way.