The ROBIN is a very simple box, but rather special in terms of quality and application
Specifications
NO solid-state transistors or ICs so NO 48V power required;
PHANTOM POWER to The Robin must be OFF;
HIGH spec transformer (E.A. Sowter) to match impedances;
BYPASS switch so that the transformer is out of circuit and you connect directly to the mic amp input. This works well with the Snow Petrel as it has a relatively high impedance input;
THE AMP JACK is connected directly to the DI JACK for a separate amplifier to be used;
EARTH LIFT disconnects the ground connection (Pin 1 of the XLR output) from the circuit in the box to prevent a hum loop which may occur if an external amplifier is used or the instrument is powered from a grounded mains supply; SWITCH GUARDS are provided to protect the switches from possible damage and the box is of very rugged construction.