JVC QL-F6

Peak of the hi-fi years : vinyl rules !

Although far less remembered than the QL-10 or QL-7, the QL-F6 has about the same motor structure as the former, the same specs as the latter - and, in spots, even surpasses both !

Bi-directional servo as in the QL-10 (and the TT-101 and TT-801), Coreless DC servomotor (as in the QL-10), continuously variable Q oil-damping for both horizontal and vertical planes, diecast aluminium cabinet, non-resonant "High-Density Pararesonance" compound frame and non-resonant "NR" one-piece headshell.
And cute pitch control with backlit needle meter à la Pioneer PLC-590.

Bi-directional servo works with a push-pull amplifier in the drive circuit : two currents are generated in each motor drive coil, one pushing and one pulling the rotor.
The result is less overshoot in speed correction, 50% increase in efficiency, 40% increase in torque and the remedy to coreless' motors lower efficiency and lower torque capability... See the JVC TT-101 page for more details.

Vertical damping is set with the perpendicular dial, horizontal damping with the top dial.
The oil is sealed inside the support column to avoid oil splashes or the need for oil replenishing.
Both dials can be set to 0 for no damping at all.

The bi-directional servo is what makes the specs equal those of the QL-10, the tonearm is what made the QL-F6... less pricey.

Despite its integrated two-planes Q damping, economies were made on the tonearm since it is of the fully automatic kind, and on the control pads which are of the mechanical kind - but only the final result counts, right ?

The F6 apparently also existed as a french Thomson TL 170T but with a simplified tonearm devoid of any Q-damping, a different platter and probably no bi-directional servo, either.