Turntable isolation

As others have mentioned, the spring and mass system has to be properly designed for it to effectively isolate. I still have an old VPI HW19 (original, not a later Mk X or Jr. version) in a closet, that I never bothered to hook up. It uses springs, but the arrangement just seems all wrong - there’s just no way it’s going to be effective. Thank god I eventually purchased a SOTA Star III, and got into vinyl right. The SOTA’s spring suspension is properly designed, and extremely effective at isolating. You'll be hard pressed to find anything more effective without getting into fancy rack systems. 

I've been considering two types of systems for isolation - active and passive.  Active versions are microprocessor controlled isolation systems (Herzan) and passive versions are spring based (MinusK).

The active solution is one-size-fits-all.  The passive solution, you have to order the unit according to the weight you are isolating.

@james1969 I can certainly vouch for the benefits of active isolation systems but they are not compatible with all turntables. For example tables with very floppy springs like the Linn may end up fighting the isolation. The TS-150 works very well with my EAR DiscMaster which has very stiff springs. You might also consider the Taiko upgrades which are both attractive and sound improving 

@folkfreak I agree, you should not have competing isolation systems which will cancel each other out.