Thank you for the question. The FX370C is an electro-acoustic guitar and so can be used directly with a guitar amplifier or suitable PA system/audio interface (connecting a jack lead from the FX370's jack socket). A built-in pre-amp is integral to the pickup system (and so you can't - and wouldn't want to - bypass the pre-amp stage).
A separate, external pre-amp (to sit between the guitar and the amp) isn't needed.
Something like our THR5A Acoustic Amplifier offers incredible performance, sound quality and effects plus a computer connection and software for editing and recording.
When not used with external amplification, the FX370C is effectively a normal acoustic guitar (the tone will be very close to our F370 model).