Linn's have never been known for having adequate isolation from vibration. By themselves, they are prone to skipping tonearms and cartridges across the disc if one is not careful. All i will say is that turntable design has come a LONG way since the design of the Linn, and even then, there were tables that were better than the Linn. Having said that and as you know, marketing is a powerful tool when it comes to high end audio.
I have reviews where they compared a few different tables in terms of their ability to resist acoustic feedback and the Linn was the worst of the bunch. In comparison, the table that was at the top of the list measured some 40 to 50 dB's better in terms of isolation. Not only does this equate to a lower noise floor and the ability to produce more resolution from within the same grooves, it also means the ability to play much louder in the listening room without losing that level of resolution.
As a side note, you might want to look into a different type of support system underneath your table. Constrained layer damping is far more effective than sheer mass in most every case. As such, i would lose some of the "rigidity" of materials underneath the player while still finding a way to keep things level.
Using this approach, not only will you put another absorbent boundary between floor-borne vibrations and the table itself, you'll have made an "energy sink" that the table itself can drain air-borne vibration into. This would be much cheaper than replacing the table itself, which is the ultimate solution to the problem you mentioned. Sean
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