Resistors R located between {HEAD ~ the non inverting terminals} of {TAIL ~ op amps} 68 and 70 to voltage sources V2 provide balanced impedences to the op amp terminals 
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Resistors R located between { HEAD ~ the non inverting terminals } of { TAIL ~ op amps } 68 and 70 to voltage sources V2 provide balanced impedences to the op amp terminals
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH