PART THREE
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THE EQUIPMENT continued Next in the chain is the A-B console mentioned previously. You can only see the 'B' section on Bernie's right, the 'A' section is covered by stuff. One of the main tools in this console is the extensive multi-band equalizer built into it. Not only is there a complete unit for Left and Right (with previews), but a matching set on the other side. The output of this console feeds the Haeco cutting amplifiers, and the cutting head on the LATHE.
This cutterhead is designed for the 45-45 standard of recording stereo on a disk. In fact, you can see these angles clearly in the design. The astute will notice more than 2 wires going in each site -- the extra pairs are for feedback coils that are fed back to the ampifier stages to reduce distortion.
In laymans' terms..."It's like having a couple of really high-quality loudspeakers wobble a needle".... The copper tubing coming in from behind is suction, to remove the material that the chisel-shaped cutting stylus shaves from the soft laquer-covered disk. The stylus is also wrapped with a small coil of wire with current going through it -- the 'hot stylus' makes a quieter, cleaner groove.
The head is mounted on a lathe base -- in fact it looks similar to ones found in machine shops. A motor turned screw, called the leadscrew, propels the carriage and the head along a linear path. The cutting computer tells the motor to go faster or slower, thus increasing the speed of the screw, and ultimately, the spacing of the grooves.
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