Or put it in another way - do you really need a buffer (impedance converter) without a gain? "Buffer linestage.pdf" is now correct file in the "Projects". Although not overly complicated (three Mos-fets and their components can be installed on small PCB), it needs rel. expensive 1:1 line OPT. Can you give us some more informations of "how and why" we need a buffer, about sound, and circuit details? BTW - nice work, again.