Altanon's chart is correct.

BTW there is no 4 Ohm option on the Vintage Modern head.

Steve

The head set to 16 Ohms and the cab switch set to mono and your speaker lead plugged into the 16 Ohm input is currently the correct set up for you. If you add the 425B to your set up then make sure that it is also set to mono and run a speaker lead from the other speaker output jack socket on the am...

All preamp valves are indeed ECC83s and V1 and V2 are shielded to prevent noise issues due to their proximity to emissions from the output transformer; they are both sensitive stages and the signal level here is very susceptible to interference (which will also be amplified!). You do not have to mat...