The diode ensures that {HEAD ~ the preamplifier} is not saturated for an impermissbly long period of time at {TAIL ~ the limit} of its operating range due to the current peaks 
The diode ensures that { HEAD ~ the preamplifier } is not saturated for an impermissbly long period of time at { TAIL ~ the limit } of its operating range due to the current peaks
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH