Croft Meganaut Dual Mono linestage using the ZPT circuit – £750 March 1, 2017June 26, 2015 by Chris A dual mono linestage using the ZPT circuit. 1 input. Copper chassis from the top Precession/Meganaut models, mains powered. Can run off 12-15 volts DC. Has a valve-like tone despite not using valves.