Check the listing for details. THR5A Desktop Modeling Acoustic Guitar Amplifier. Condition: Open box. Listed at 212.89 USD. The THR5A from Yamaha is a desktop modeling guitar amp that simulates four different microphone types and is specifically designed for use with electric-acoustic and silent guitars. In contrast to normal stage amplifiers, the THR5A is intended for off-stage uses such as recording and practicing. Equipped with a USB port, the amp is capable of being used in conjunction with your computer for advanced editing of guitar sounds, recording and playback using the included software package.The THR5A is equipped with a 1/4" guitar input as well as an 1/8" aux input that can be used for connecting your mp3 player for jamming along to backing tracks. The two full range 3" speakers are designed to accurately reproduce stereo playback from the 1/8" input as well as the sound of your guitar without the.