Could it have been how the performer had it set up? ...

YEARS ago, when I was still playing accordion, I went to hear a group with the sax player in our band ... the accordion player had the exact set up I had - SANO accordion and SANO 'Stereo' amp, but it sounded very 'tinny' ... they asked me and the sax player to sit in, and I adjusted the sound of the amp to suit me ... after a couple of songs the accordion player commented on how good the accordion sounded ... I told him I had made a number of adjustments ... when he went to play, he changed all the settings back to where he had them ... ???