Disclosed is {HEAD ~ a differential amplifier} including an emitter follower pair, a first differential pair, and {TAIL ~ a main differential amplifier} 
Disclosed is { HEAD ~ a differential amplifier } including an emitter follower pair , a first differential pair , and { TAIL ~ a main differential amplifier }
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL