Hi all, I'm starting ordering parts to build the excellent Blackvibe by @robrob, but I have some questions, and figured I would as you, dear amp gurus First about the output transformer. The one I ordered is a Hammond 1760J https://www.hammfg.com/part/1760J (being in Europe doesn't make it easy to order the recommended parts, sorry) and it has multiple possible impedances (4, 8 and 16 Ohms). Because of this I'm thinking of having multiple jack outputs for being able to switch cabinets with possibly different impedances. So I was wondering if connecting the three NFB from the 3 jacks would work, or if I need a switching system to make sure that only the NFB loop of the connected speaker connected? Another question to avoid the problem when there isn't a load on the OT (no speaker connected), why isn't a switched jack used with a resistor coupled when no speaker is connected? Or is shunting to ground enough and safe? Thanks in advance!