... Beltrami is on good terms with Nello Menghescini.. they are both top notch builders..and Betrami does custom tuning for Castagnari, Baffetti, and most likey for Nello.
... Beltrami is in Stradella ( the second city for accordion production in Italy.. which has dwindled to only a couple makes.. mostly jobbed to Castelfidardo )..
... The TUNING tradition in Stradella is quite famous... They have a different technique and do more shades of tuning.. and .. are best known for being able to tune to keep volume very balanced , even on the higher notes, where on diatonics you can lose volume...