I've done the Fromel mod with full recap, Billm hi voltage pre-amp mod, presence control mod. When I received the Billm TO-22 output transformer the AUX Spkr prewire socket was missing. I'm assuming the the extra yellow wire on the OT is for the auto ohms switching? Can it be hooked up like the old one came out and leave the yellow wire unhooked? ( it would be insolated to prevent shorting). Until I receive, or buy a new oitput switch jack.