[en] A preamplifier allowing an increase in the sensitivity of the already producted DELPHI Hadron Calorimeter front-end electronics up to 0.1 pC is described. The presented preamplfier permits a considerable reduction of the gas gain and transition to the saturated avalanche mode region. The HC barrel module characteristics in the proportional mode of its detectors operation are found out. The possibility of selecting muon track in the HC and using them for detector triggering has been investigated. It is shown that the transition to the proportional mode does not worsen the main characteristics of HC and the reliability of its detectors will be considerably incresed. 11 refs.; 11 figs