“The STR-X was built to be a simple but powerful, digitally-oriented guitar amp, one which isn’t based off of any pre-existing analog models. Tonally, it is capable of high gain, modest crunch, and cleaner tones with some added heat.
Mode: The Mode control in the center of the amp changes the crossover point that feeds the pre-amp distortion (after the “X” pedal-style distortion). Normal will give you a solid low-end, with retained clarity in the mids and highs even when cranked. Thick drops the crossover point lower, resulting in greater intermodulation of the distorted signal, and a fuzzy tone ready for a sludge or doom sound. Finally, Open separates all of the low-end from the mids and highs for a tight and bright tone, perfect for fast palm-muted playing or any situation where the low-end of the other two modes might be excessive.
X: This mysterious knob works like a one-knob distortion pedal (inspired by the Ibanez Tube Screamer), with filters that focus the tone on the mid-range the further it’s driven—good for an extra bump before the amp, dialing in a lead tone that cuts through everything else, or for tightening the bass on Thick mode while still remaining truly Thick.
Gain: This is the pre-amp drive section, ranging from not-quite-clean to a heavy wall of distortion. At high gain, the texture varies significantly, depending on the Mode used. This stage generates asymmetric distortion and both even and odd harmonics.
Master: This knob provides the output gain of the amp, with added distortion as well. Although not claiming to emulate any particular type of tube, it does generate the symmetric, odd-harmonic distortion you’d expect from pentode tubes. With low pre-amp gain, you can use this knob to dial in fairly clean tones down low, and bright crunch up high.
New In v1.1::
- Mac OS X Catalina/Big Sur and M1 Mac Support.
- 4x oversampling with option for higher-quality, linear phase oversampling when rendering.
- “De-kinked” preamp distortion algorithm for more accurate asymmetrical distortion.
- Expanded range of tone controls.
- Allow option for using v1.0 tone controls.
- Fully resizable GUI (VST3 only).”
Source : kvraudio.com