Guy's, I'm using the First Watt (F3) or the output of the si2A3/45 with good results (Moar Powah!!). The band-aid of the EF-5 doesn't cut it:cool:!! The schmaltz and euphony are gone when more, and better controlled power is used! Great presentation with a wealth of details, the notes and sounds (a majority of them) used to stick to the diaphram...no longer!