I stand corrected on the mass of the Hadcock, it is indeed a medium mass arm as Audiofeil says. I was thinking of the original Hadcocks, which were low mass arms. In terms of Hadcock and Music Maker, I only know what I read, which is that the Music Maker and Hadcock are designed to go together, and that the two have a connection via the owner of Music Maker (possibly British distributor of Hadcock?), although Bill (Audiofeil) may have more info on the exact connection than I do.