  The evaporation residue yields from compound nuclei $^{220}$Th formed in the
$^{16}$O+$^{204}$Pb, $^{40}$Ar+$^{180}$Hf, $^{82}$Se+$^{138}$Ba,
$^{124}$Sn+$^{96}$Zr reactions are analyzed to study the entrance channel
effects by comparison of the capture, fusion and evaporation residue cross
sections calculated by the combined dinuclear system (DNS) and advanced
statistical models. The difference between evaporation residue (ER) cross
sections can be related to the stages of compound nucleus formation or/and at
its surviving against fission. The sensitivity of the both stages in the
evolution of DNS up to the evaporation residue formation to the angular
momentum of DNS is studied. The difference between fusion excitation functions
are explained by the hindrance to complete fusion due to the larger intrinsic
fusion barrier $B^*_{\rm fus}$ for the transformation of the DNS into a
compound nucleus and the increase of the quasifission contribution due to the
decreasing of quasifission barrier $B_{\rm qf}$ as a function of the angular
momentum. The largest value of the ER residue yields in the very mass
asymmetric $^{16}$O+$^{204}$Pb reaction is related to the large fusion
probability and to the relatively low threshold of the excitation energy of the
compound nucleus. Due to the large threshold of the excitation energy (35 MeV)
of the $^{40}$Ar+$^{180}$Hf reaction, it produces less the ER yields than the
almost mass symmetric $^{82}$Se+$^{138}$Ba reaction having the lowest threshold
value (12 MeV).
