I'm a newbie on this forum....I studied piano accordion for 12 years back in the 50's-60's from Frank Marocco (we never knew then how important he would be - just that he was a fantastic teacher!). I took 2 years of music theory in high school (the subject was called "Harmony" back in the 60's) and found that the basis of much of music theory ("the cycle of 5ths") was second nature....as it was the layout of the accordion bass keys. The accordion curriculum Frank taught was the "Palmer Hughes Accordion Method" - a *fantastic* set of 12 books which I've already commented on elsewhere in the forum. Frank referred us to technicians who made my accordion "amplified" by the installation of a small metal device with two knobs (known in the vernacular as the "pickup") - it was installed (if memory serves) on the right side near the bottom (highest treble keys) and attached via a cord to a tube-based amplifier. That whole setup allowed the accordion to sound very much like a pipe organ - and allowed me to play Bach's venerable "Toccata *and* Fugue in D minor" ( emphasis mine) with a close approximation of the sound of a pipe organ (if you closed your eyes and just listened). Lots of fun and great technical accomplishment back then ...but alas, the instrument by the late 60's had become primarily a method for crude jokes and insults. If anyone remembers any of this kind of techology (or of having Frank as a teacher or mentor) I'd love to hear from them.