Scott at Electrodrone made us this amazing device that can function as either a 4watt amp head or a tube preamp/overdrive. The speaker out jack is switching, so when no speaker is connected, a resistive load goes into circuit allowing it to function as an overdrive box. Much thanks to Scott for adding our request at very late stage in the design: a relay-based bypass footswitch circuit. This is an original design but Scott tip his hat to the late Gar Gillies (Garnet), whose Herzog design was an inspiration .

As with the ZB50, he named it after a motorcycle, in this case the British Ariel Square Four: