With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: As preparations were made for a tour of the US, the Beatles hired acoustics engineers to ensure that their music could be heard. Having originally used Vox AC30 amplifiers, they later acquired more powerful 100-watt amplifiers, specially designed by Vox for them as they moved into larger venues in 1964, but these were still inadequate. Struggling to compete with the volume of sound generated by screaming fans, the band had grown increasingly bored with the routine of performing live. Recognising that their shows were no longer about the music, they decided to make the August tour their last.
text_B: From the way that the passage is written, could you confidently say that the Beatles' disillusionment with performing live came about before they even played their first show of this tour (as opposed to the band losing their enthusiasm as a result of what happened at that same tour's shows)?
NO.