There's really no such thing as the complete absence of a plinth. In a typical DD table, the motor is often mounted to a chassis, usually an aluminum enclosure, like the SP10 or Halcro's TT81. And to me that's a plinth already.
The best experiment, I think, is take the motor out and place it bare naked on a platform, perhaps supported by tip-toes and might need to be held down by something (which can open another can of worms) because the start-up torque might jerk the the motor out of placement in relationship to the tonearm geometry, unless the casing for the motor is really hefty. Essentially, a comparison between yes-chassis and no-chassis. Naked motor and not so naked motor. Anyone wanna try that?
If the naked motor sounds better, then a NO-PLINTHER can wear his/her t-shirt proud.
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