Now, about the theory: The difference between major and minor chords is this: A major chord consists of a 1st, 3rd, and 5th degree of a major scale while a minor chord is made from the 1st, flatted 3rd, and 5th degrees of a major scale. So the only difference is the 3rd degree. You can see this clearly when you compare certain chords such as an open A Major with an open A Minor chord. The only difference is the note on the second string; changing that one note profoundly affects the sound.
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