This is the schematic for the Tubelab SSE amplifier. All optional features are shown. The mode (Triode / UL) switch, the Cathode feedback switch, the standby switch, and the rectifier switch are optional, and should be hard wired into the desired position if they are not used. The optional power supply choke and the optional auxiliary power supply capacitor are simply left out if not used. R1 and the choke should not be used at the same time. Install one or the other. A choke (even a cheap one) is recommended if high efficiency speakers are used.