[QuadList] Ampex AST heads and CMC DPT heads--what's different?

[Dennis Degan]

		On May 8, 2010, at 5:37 PM, Wayne Watson wrote:

 > The AST head was actually split across and lengthwise. Across, and  
then wired polarity opposite, to correct for the Zenith problem.  
Lengthwise (a more narrow strip) to provide feedback position; what  
direction and how much it was bent would give a voltage.

		I add:

	This would make the complete AST system a closed-loop servo.  The  
narrow piezo strip was the key to making it work.

			Dennis Degan, Video Editor-Consultant-Knowledge Bank
	  					NBC Today Show, New York