Part of the VTX Series, the Valvetronix Vt40X is a perfect combination of innovation and tradition. These amps combine sophisticated modeling technology with a multi-stage tube pre-amp circuit to reproduce the unique distortion, touch sensitivity, and the response that is characteristic of classic tube amps. Its unique modeling algorithm actually recreates the analog circuits of some of the most coveted tube amplifiers and allows you to adjust the gain structure and bias of the internal tube in real time. Also, when using certain models, the amp can be switched between Class A and Class AB operation. The effects section has also been revamped and now offers 12 classic effects based on some of the most iconic stompboxes of all time. These amps also feature a USB port, which allows you to connect the amplifier to their PC, Mac, or i OS device (with optional USB Camera Adapter Kit) and manage programs and customize amps and effects by using VOX's Tone Room software. The Tone Room software allows for deep editing of all of the great amps and effects so you can carefully craft your sound, which can then be saved as one of the eight customizable programs. There is also a built-in tuner, an AUX-in jack for jamming along with recorded music, and a headphone jack for silent practice.