I don't know what the original caps were, or the values, but the Special Edition upgrade offered by SF used MultiCap RTX polystyrene capacitors, and the SE plus upgrade currently offered through Partsconnexion uses Audio Note Silver Foil capacitors. I will be receiving a Line 3 SE any day now, and can then compare it with the Line 2 SE I currently own, relative to bass response. The Line 2 already goes pretty deep, but the bass is just not quite as tight as with my SS preamp. The bass of the Line 3 is supposed to be improved over the Line 2. It sounds like maybe someone has been experimenting on yours. You could call Chris Johnson at Partsconnexion who would know what the values were, and maybe sell you some of the Audio Note caps. Let us know what you do and how it works out.