As we record all demo sounds by ourselves, not every preset has its own original demo sound. For such presets we've recorded a default demo, so you can still understand how the preset sounds like. We are constantly adding original demo sounds, so sooner or later every preset will have its original demo.
FYI Here is a tab for the default demo: https://tabs.ultimate-guitar.com/m/misc_soundtrack/tonebridge_default_demo_guitar_pro.htm