"Though you will find a lot of well-known names among these modules, we do not pretend to imitate a real, physical amp. Some of our modules sound pretty close to well known originals, we took a lot of time and care to provide you with the characteristics of popular legends. But we still see Guitarix as an amp in its own right. It sounds the way you set it up and you are encouraged to try the wildest combinations to make guitarix your very own personal amplifier."
Tonestack adds to Guitarix the tone-response of a few legendary amps. It brings a 3 band equalizer which provide us the Bass, Mid and Treble controls of these virtual amps.
The models included on Guitarix 0.19 are (and act like):
Wiki: Amp2
Wiki: Cabinet_Impulse_Response_convolution
Wiki: Full-Features
Wiki: Tone_controls