A supplementary playback head on a tape recorder designed for reproducing the master tapes for the production of phonograph records. The signal from the preview head tells the variable-pitch circuitry on the cutting lathe the program amplitude level that it will cut one groove later. This allows the unit to space the grooves so that they do not intersect due to amplitude transients. In quieter passages, it allows the circuit to pack the grooves more closely, minimizing land.