The Tech 21 is a little pedal that features (from right to left) a boost, Plexi Distortion, a Sans Amp and a Tap Delay. You can directly plug it in the PA or in front of an amp.
Of all the pedal models, this is the most sophisticated. Its unconventional design not only keeps the unit compact, it is key to the wide range of sounds you can achieve.
?Architecturally? create your own rig in seconds. You can easily achieve the most sought-after tube amp sounds, and entirely new ones as well. Choose amplifier type, modification and speaker cabinet/mic placement configurations. You can easily mix and match specific sound characteristics in ways that would otherwise be physically improbable, probably impractical and definitely not cost effective. The GT2 is a truckload of great amps in a single, simple pedal.