So in lots of Tomos's video's for example this lesson. B12 Barre Chords - Major, minor - Analyze a Song. He teaches a concept which he describes very well but then he does this solo where he is obviously playing the whole fret board. In the triad videos he does the same - teaches you to play triads then solos using the whole fretboard.
Can someone explain the theory behind what he is doing there?
I just watched the B12 video. I think the solo is showing that he is following chords that he just analyzed. He is using the notes in the chords, R, M3, minor 3, and 5, prominently in the solo, but not just playing scales over the chord progression. For each chord (playing in his head), he knows what notes and/or triads to play. And of course he knows those notes and triads all over the fretboard.
Here is Tomo's comment:
"Thank you so much for subscribing to my Guitar Wisdom. In each video, the most important thing is to follow the main topic. I play a little demo at the beginning or near the end, but this is, for the most part, something for you to enjoy. I follow the chord changes and play some triads . . . then, I add something more."